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Copyright (C) 2006-2013 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Funding Free Software", the Front-Cover texts
being (a) (see below), and with the Back-Cover Texts being (b) (see
below). A copy of the license is included in the section entitled "GNU
Free Documentation License".
(a) The FSF's Front-Cover Text is:
A GNU Manual
(b) The FSF's Back-Cover Text is:
You have freedom to copy and modify this GNU Manual, like GNU
software. Copies published by the Free Software Foundation raise
funds for GNU development.
INFO-DIR-SECTION GNU Libraries
START-INFO-DIR-ENTRY
* libgomp: (libgomp). GNU OpenMP runtime library
END-INFO-DIR-ENTRY
This manual documents the GNU implementation of the OpenMP API for
multi-platform shared-memory parallel programming in C/C++ and Fortran.
Published by the Free Software Foundation 51 Franklin Street, Fifth
Floor Boston, MA 02110-1301 USA
Copyright (C) 2006-2013 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Funding Free Software", the Front-Cover texts
being (a) (see below), and with the Back-Cover Texts being (b) (see
below). A copy of the license is included in the section entitled "GNU
Free Documentation License".
(a) The FSF's Front-Cover Text is:
A GNU Manual
(b) The FSF's Back-Cover Text is:
You have freedom to copy and modify this GNU Manual, like GNU
software. Copies published by the Free Software Foundation raise
funds for GNU development.

File: libgomp.info, Node: Top, Next: Enabling OpenMP, Up: (dir)
Introduction
************
This manual documents the usage of libgomp, the GNU implementation of
the OpenMP (http://www.openmp.org) Application Programming Interface
(API) for multi-platform shared-memory parallel programming in C/C++
and Fortran.
* Menu:
* Enabling OpenMP:: How to enable OpenMP for your applications.
* Runtime Library Routines:: The OpenMP runtime application programming
interface.
* Environment Variables:: Influencing runtime behavior with environment
variables.
* The libgomp ABI:: Notes on the external ABI presented by libgomp.
* Reporting Bugs:: How to report bugs in GNU OpenMP.
* Copying:: GNU general public license says
how you can copy and share libgomp.
* GNU Free Documentation License::
How you can copy and share this manual.
* Funding:: How to help assure continued work for free
software.
* Library Index:: Index of this documentation.

File: libgomp.info, Node: Enabling OpenMP, Next: Runtime Library Routines, Prev: Top, Up: Top
1 Enabling OpenMP
*****************
To activate the OpenMP extensions for C/C++ and Fortran, the
compile-time flag `-fopenmp' must be specified. This enables the OpenMP
directive `#pragma omp' in C/C++ and `!$omp' directives in free form,
`c$omp', `*$omp' and `!$omp' directives in fixed form, `!$' conditional
compilation sentinels in free form and `c$', `*$' and `!$' sentinels in
fixed form, for Fortran. The flag also arranges for automatic linking
of the OpenMP runtime library (*note Runtime Library Routines::).
A complete description of all OpenMP directives accepted may be
found in the OpenMP Application Program Interface
(http://www.openmp.org) manual, version 3.1.

File: libgomp.info, Node: Runtime Library Routines, Next: Environment Variables, Prev: Enabling OpenMP, Up: Top
2 Runtime Library Routines
**************************
The runtime routines described here are defined by section 3 of the
OpenMP specifications in version 3.1. The routines are structured in
following three parts:
Control threads, processors and the parallel environment.
* Menu:
* omp_get_active_level:: Number of active parallel regions
* omp_get_ancestor_thread_num:: Ancestor thread ID
* omp_get_dynamic:: Dynamic teams setting
* omp_get_level:: Number of parallel regions
* omp_get_max_active_levels:: Maximum number of active regions
* omp_get_max_threads:: Maximum number of threads of parallel region
* omp_get_nested:: Nested parallel regions
* omp_get_num_procs:: Number of processors online
* omp_get_num_threads:: Size of the active team
* omp_get_schedule:: Obtain the runtime scheduling method
* omp_get_team_size:: Number of threads in a team
* omp_get_thread_limit:: Maximum number of threads
* omp_get_thread_num:: Current thread ID
* omp_in_parallel:: Whether a parallel region is active
* omp_in_final:: Whether in final or included task region
* omp_set_dynamic:: Enable/disable dynamic teams
* omp_set_max_active_levels:: Limits the number of active parallel regions
* omp_set_nested:: Enable/disable nested parallel regions
* omp_set_num_threads:: Set upper team size limit
* omp_set_schedule:: Set the runtime scheduling method
Initialize, set, test, unset and destroy simple and nested locks.
* Menu:
* omp_init_lock:: Initialize simple lock
* omp_set_lock:: Wait for and set simple lock
* omp_test_lock:: Test and set simple lock if available
* omp_unset_lock:: Unset simple lock
* omp_destroy_lock:: Destroy simple lock
* omp_init_nest_lock:: Initialize nested lock
* omp_set_nest_lock:: Wait for and set simple lock
* omp_test_nest_lock:: Test and set nested lock if available
* omp_unset_nest_lock:: Unset nested lock
* omp_destroy_nest_lock:: Destroy nested lock
Portable, thread-based, wall clock timer.
* Menu:
* omp_get_wtick:: Get timer precision.
* omp_get_wtime:: Elapsed wall clock time.

File: libgomp.info, Node: omp_get_active_level, Next: omp_get_ancestor_thread_num, Up: Runtime Library Routines
2.1 `omp_get_active_level' - Number of parallel regions
=======================================================
_Description_:
This function returns the nesting level for the active parallel
blocks, which enclose the calling call.
_C/C++_
_Prototype_: `int omp_get_active_level(void);'
_Fortran_:
_Interface_: `integer function omp_get_active_level()'
_See also_:
*note omp_get_level::, *note omp_get_max_active_levels::, *note
omp_set_max_active_levels::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.19.

File: libgomp.info, Node: omp_get_ancestor_thread_num, Next: omp_get_dynamic, Prev: omp_get_active_level, Up: Runtime Library Routines
2.2 `omp_get_ancestor_thread_num' - Ancestor thread ID
======================================================
_Description_:
This function returns the thread identification number for the
given nesting level of the current thread. For values of LEVEL
outside zero to `omp_get_level' -1 is returned; if LEVEL is
`omp_get_level' the result is identical to `omp_get_thread_num'.
_C/C++_
_Prototype_: `int omp_get_ancestor_thread_num(int level);'
_Fortran_:
_Interface_: `integer function omp_get_ancestor_thread_num(level)'
`integer level'
_See also_:
*note omp_get_level::, *note omp_get_thread_num::, *note
omp_get_team_size::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.17.

File: libgomp.info, Node: omp_get_dynamic, Next: omp_get_level, Prev: omp_get_ancestor_thread_num, Up: Runtime Library Routines
2.3 `omp_get_dynamic' - Dynamic teams setting
=============================================
_Description_:
This function returns `true' if enabled, `false' otherwise. Here,
`true' and `false' represent their language-specific counterparts.
The dynamic team setting may be initialized at startup by the
`OMP_DYNAMIC' environment variable or at runtime using
`omp_set_dynamic'. If undefined, dynamic adjustment is disabled by
default.
_C/C++_:
_Prototype_: `int omp_get_dynamic(void);'
_Fortran_:
_Interface_: `logical function omp_get_dynamic()'
_See also_:
*note omp_set_dynamic::, *note OMP_DYNAMIC::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.2.8.

File: libgomp.info, Node: omp_get_level, Next: omp_get_max_active_levels, Prev: omp_get_dynamic, Up: Runtime Library Routines
2.4 `omp_get_level' - Obtain the current nesting level
======================================================
_Description_:
This function returns the nesting level for the parallel blocks,
which enclose the calling call.
_C/C++_
_Prototype_: `int omp_get_level(void);'
_Fortran_:
_Interface_: `integer function omp_level()'
_See also_:
*note omp_get_active_level::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.16.

File: libgomp.info, Node: omp_get_max_active_levels, Next: omp_get_max_threads, Prev: omp_get_level, Up: Runtime Library Routines
2.5 `omp_get_max_active_levels' - Maximum number of active regions
==================================================================
_Description_:
This function obtains the maximum allowed number of nested, active
parallel regions.
_C/C++_
_Prototype_: `int omp_get_max_active_levels(void);'
_Fortran_:
_Interface_: `integer function omp_get_max_active_levels()'
_See also_:
*note omp_set_max_active_levels::, *note omp_get_active_level::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.15.

File: libgomp.info, Node: omp_get_max_threads, Next: omp_get_nested, Prev: omp_get_max_active_levels, Up: Runtime Library Routines
2.6 `omp_get_max_threads' - Maximum number of threads of parallel region
========================================================================
_Description_:
Return the maximum number of threads used for the current parallel
region that does not use the clause `num_threads'.
_C/C++_:
_Prototype_: `int omp_get_max_threads(void);'
_Fortran_:
_Interface_: `integer function omp_get_max_threads()'
_See also_:
*note omp_set_num_threads::, *note omp_set_dynamic::, *note
omp_get_thread_limit::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.2.3.

File: libgomp.info, Node: omp_get_nested, Next: omp_get_num_procs, Prev: omp_get_max_threads, Up: Runtime Library Routines
2.7 `omp_get_nested' - Nested parallel regions
==============================================
_Description_:
This function returns `true' if nested parallel regions are
enabled, `false' otherwise. Here, `true' and `false' represent
their language-specific counterparts.
Nested parallel regions may be initialized at startup by the
`OMP_NESTED' environment variable or at runtime using
`omp_set_nested'. If undefined, nested parallel regions are
disabled by default.
_C/C++_:
_Prototype_: `int omp_get_nested(void);'
_Fortran_:
_Interface_: `logical function omp_get_nested()'
_See also_:
*note omp_set_nested::, *note OMP_NESTED::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.10.

File: libgomp.info, Node: omp_get_num_procs, Next: omp_get_num_threads, Prev: omp_get_nested, Up: Runtime Library Routines
2.8 `omp_get_num_procs' - Number of processors online
=====================================================
_Description_:
Returns the number of processors online.
_C/C++_:
_Prototype_: `int omp_get_num_procs(void);'
_Fortran_:
_Interface_: `integer function omp_get_num_procs()'
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.2.5.

File: libgomp.info, Node: omp_get_num_threads, Next: omp_get_schedule, Prev: omp_get_num_procs, Up: Runtime Library Routines
2.9 `omp_get_num_threads' - Size of the active team
===================================================
_Description_:
Returns the number of threads in the current team. In a sequential
section of the program `omp_get_num_threads' returns 1.
The default team size may be initialized at startup by the
`OMP_NUM_THREADS' environment variable. At runtime, the size of
the current team may be set either by the `NUM_THREADS' clause or
by `omp_set_num_threads'. If none of the above were used to define
a specific value and `OMP_DYNAMIC' is disabled, one thread per CPU
online is used.
_C/C++_:
_Prototype_: `int omp_get_num_threads(void);'
_Fortran_:
_Interface_: `integer function omp_get_num_threads()'
_See also_:
*note omp_get_max_threads::, *note omp_set_num_threads::, *note
OMP_NUM_THREADS::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.2.2.

File: libgomp.info, Node: omp_get_schedule, Next: omp_get_team_size, Prev: omp_get_num_threads, Up: Runtime Library Routines
2.10 `omp_get_schedule' - Obtain the runtime scheduling method
==============================================================
_Description_:
Obtain the runtime scheduling method. The KIND argument will be
set to the value `omp_sched_static', `omp_sched_dynamic',
`omp_sched_guided' or `omp_sched_auto'. The second argument,
MODIFIER, is set to the chunk size.
_C/C++_
_Prototype_: `void omp_schedule(omp_sched_t *kind, int *modifier);'
_Fortran_:
_Interface_: `subroutine omp_schedule(kind, modifier)'
`integer(kind=omp_sched_kind) kind'
`integer modifier'
_See also_:
*note omp_set_schedule::, *note OMP_SCHEDULE::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.12.

File: libgomp.info, Node: omp_get_team_size, Next: omp_get_thread_limit, Prev: omp_get_schedule, Up: Runtime Library Routines
2.11 `omp_get_team_size' - Number of threads in a team
======================================================
_Description_:
This function returns the number of threads in a thread team to
which either the current thread or its ancestor belongs. For
values of LEVEL outside zero to `omp_get_level', -1 is returned;
if LEVEL is zero, 1 is returned, and for `omp_get_level', the
result is identical to `omp_get_num_threads'.
_C/C++_:
_Prototype_: `int omp_get_team_size(int level);'
_Fortran_:
_Interface_: `integer function omp_get_team_size(level)'
`integer level'
_See also_:
*note omp_get_num_threads::, *note omp_get_level::, *note
omp_get_ancestor_thread_num::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.18.

File: libgomp.info, Node: omp_get_thread_limit, Next: omp_get_thread_num, Prev: omp_get_team_size, Up: Runtime Library Routines
2.12 `omp_get_thread_limit' - Maximum number of threads
=======================================================
_Description_:
Return the maximum number of threads of the program.
_C/C++_:
_Prototype_: `int omp_get_thread_limit(void);'
_Fortran_:
_Interface_: `integer function omp_get_thread_limit()'
_See also_:
*note omp_get_max_threads::, *note OMP_THREAD_LIMIT::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.13.

File: libgomp.info, Node: omp_get_thread_num, Next: omp_in_parallel, Prev: omp_get_thread_limit, Up: Runtime Library Routines
2.13 `omp_get_thread_num' - Current thread ID
=============================================
_Description_:
Returns a unique thread identification number within the current
team. In a sequential parts of the program, `omp_get_thread_num'
always returns 0. In parallel regions the return value varies from
0 to `omp_get_num_threads'-1 inclusive. The return value of the
master thread of a team is always 0.
_C/C++_:
_Prototype_: `int omp_get_thread_num(void);'
_Fortran_:
_Interface_: `integer function omp_get_thread_num()'
_See also_:
*note omp_get_num_threads::, *note omp_get_ancestor_thread_num::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.2.4.

File: libgomp.info, Node: omp_in_parallel, Next: omp_in_final, Prev: omp_get_thread_num, Up: Runtime Library Routines
2.14 `omp_in_parallel' - Whether a parallel region is active
============================================================
_Description_:
This function returns `true' if currently running in parallel,
`false' otherwise. Here, `true' and `false' represent their
language-specific counterparts.
_C/C++_:
_Prototype_: `int omp_in_parallel(void);'
_Fortran_:
_Interface_: `logical function omp_in_parallel()'
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.2.6.

File: libgomp.info, Node: omp_in_final, Next: omp_set_dynamic, Prev: omp_in_parallel, Up: Runtime Library Routines
2.15 `omp_in_final' - Whether in final or included task region
==============================================================
_Description_:
This function returns `true' if currently running in a final or
included task region, `false' otherwise. Here, `true' and `false'
represent their language-specific counterparts.
_C/C++_:
_Prototype_: `int omp_in_final(void);'
_Fortran_:
_Interface_: `logical function omp_in_final()'
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.20.

File: libgomp.info, Node: omp_set_dynamic, Next: omp_set_max_active_levels, Prev: omp_in_final, Up: Runtime Library Routines
2.16 `omp_set_dynamic' - Enable/disable dynamic teams
=====================================================
_Description_:
Enable or disable the dynamic adjustment of the number of threads
within a team. The function takes the language-specific equivalent
of `true' and `false', where `true' enables dynamic adjustment of
team sizes and `false' disables it.
_C/C++_:
_Prototype_: `void omp_set_dynamic(int set);'
_Fortran_:
_Interface_: `subroutine omp_set_dynamic(set)'
`logical, intent(in) :: set'
_See also_:
*note OMP_DYNAMIC::, *note omp_get_dynamic::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.2.7.

File: libgomp.info, Node: omp_set_max_active_levels, Next: omp_set_nested, Prev: omp_set_dynamic, Up: Runtime Library Routines
2.17 `omp_set_max_active_levels' - Limits the number of active parallel regions
===============================================================================
_Description_:
This function limits the maximum allowed number of nested, active
parallel regions.
_C/C++_
_Prototype_: `void omp_set_max_active_levels(int max_levels);'
_Fortran_:
_Interface_: `subroutine omp_set_max_active_levels(max_levels)'
`integer max_levels'
_See also_:
*note omp_get_max_active_levels::, *note omp_get_active_level::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.14.

File: libgomp.info, Node: omp_set_nested, Next: omp_set_num_threads, Prev: omp_set_max_active_levels, Up: Runtime Library Routines
2.18 `omp_set_nested' - Enable/disable nested parallel regions
==============================================================
_Description_:
Enable or disable nested parallel regions, i.e., whether team
members are allowed to create new teams. The function takes the
language-specific equivalent of `true' and `false', where `true'
enables dynamic adjustment of team sizes and `false' disables it.
_C/C++_:
_Prototype_: `void omp_set_nested(int set);'
_Fortran_:
_Interface_: `subroutine omp_set_nested(set)'
`logical, intent(in) :: set'
_See also_:
*note OMP_NESTED::, *note omp_get_nested::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.2.9.

File: libgomp.info, Node: omp_set_num_threads, Next: omp_set_schedule, Prev: omp_set_nested, Up: Runtime Library Routines
2.19 `omp_set_num_threads' - Set upper team size limit
======================================================
_Description_:
Specifies the number of threads used by default in subsequent
parallel sections, if those do not specify a `num_threads' clause.
The argument of `omp_set_num_threads' shall be a positive integer.
_C/C++_:
_Prototype_: `void omp_set_num_threads(int n);'
_Fortran_:
_Interface_: `subroutine omp_set_num_threads(n)'
`integer, intent(in) :: n'
_See also_:
*note OMP_NUM_THREADS::, *note omp_get_num_threads::, *note
omp_get_max_threads::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.2.1.

File: libgomp.info, Node: omp_set_schedule, Next: omp_init_lock, Prev: omp_set_num_threads, Up: Runtime Library Routines
2.20 `omp_set_schedule' - Set the runtime scheduling method
===========================================================
_Description_:
Sets the runtime scheduling method. The KIND argument can have the
value `omp_sched_static', `omp_sched_dynamic', `omp_sched_guided'
or `omp_sched_auto'. Except for `omp_sched_auto', the chunk size
is set to the value of MODIFIER if positive, or to the default
value if zero or negative. For `omp_sched_auto' the MODIFIER
argument is ignored.
_C/C++_
_Prototype_: `void omp_set_schedule(omp_sched_t *kind, int
*modifier);'
_Fortran_:
_Interface_: `subroutine omp_set_schedule(kind, modifier)'
`integer(kind=omp_sched_kind) kind'
`integer modifier'
_See also_:
*note omp_get_schedule:: *note OMP_SCHEDULE::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section
3.2.11.

File: libgomp.info, Node: omp_init_lock, Next: omp_set_lock, Prev: omp_set_schedule, Up: Runtime Library Routines
2.21 `omp_init_lock' - Initialize simple lock
=============================================
_Description_:
Initialize a simple lock. After initialization, the lock is in an
unlocked state.
_C/C++_:
_Prototype_: `void omp_init_lock(omp_lock_t *lock);'
_Fortran_:
_Interface_: `subroutine omp_init_lock(lock)'
`integer(omp_lock_kind), intent(out) :: lock'
_See also_:
*note omp_destroy_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.1.

File: libgomp.info, Node: omp_set_lock, Next: omp_test_lock, Prev: omp_init_lock, Up: Runtime Library Routines
2.22 `omp_set_lock' - Wait for and set simple lock
==================================================
_Description_:
Before setting a simple lock, the lock variable must be
initialized by `omp_init_lock'. The calling thread is blocked
until the lock is available. If the lock is already held by the
current thread, a deadlock occurs.
_C/C++_:
_Prototype_: `void omp_set_lock(omp_lock_t *lock);'
_Fortran_:
_Interface_: `subroutine omp_set_lock(lock)'
`integer(omp_lock_kind), intent(inout) :: lock'
_See also_:
*note omp_init_lock::, *note omp_test_lock::, *note
omp_unset_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.3.

File: libgomp.info, Node: omp_test_lock, Next: omp_unset_lock, Prev: omp_set_lock, Up: Runtime Library Routines
2.23 `omp_test_lock' - Test and set simple lock if available
============================================================
_Description_:
Before setting a simple lock, the lock variable must be
initialized by `omp_init_lock'. Contrary to `omp_set_lock',
`omp_test_lock' does not block if the lock is not available. This
function returns `true' upon success, `false' otherwise. Here,
`true' and `false' represent their language-specific counterparts.
_C/C++_:
_Prototype_: `int omp_test_lock(omp_lock_t *lock);'
_Fortran_:
_Interface_: `logical function omp_test_lock(lock)'
`integer(omp_lock_kind), intent(inout) :: lock'
_See also_:
*note omp_init_lock::, *note omp_set_lock::, *note omp_set_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.5.

File: libgomp.info, Node: omp_unset_lock, Next: omp_destroy_lock, Prev: omp_test_lock, Up: Runtime Library Routines
2.24 `omp_unset_lock' - Unset simple lock
=========================================
_Description_:
A simple lock about to be unset must have been locked by
`omp_set_lock' or `omp_test_lock' before. In addition, the lock
must be held by the thread calling `omp_unset_lock'. Then, the
lock becomes unlocked. If one or more threads attempted to set the
lock before, one of them is chosen to, again, set the lock to
itself.
_C/C++_:
_Prototype_: `void omp_unset_lock(omp_lock_t *lock);'
_Fortran_:
_Interface_: `subroutine omp_unset_lock(lock)'
`integer(omp_lock_kind), intent(inout) :: lock'
_See also_:
*note omp_set_lock::, *note omp_test_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.4.

File: libgomp.info, Node: omp_destroy_lock, Next: omp_init_nest_lock, Prev: omp_unset_lock, Up: Runtime Library Routines
2.25 `omp_destroy_lock' - Destroy simple lock
=============================================
_Description_:
Destroy a simple lock. In order to be destroyed, a simple lock
must be in the unlocked state.
_C/C++_:
_Prototype_: `void omp_destroy_lock(omp_lock_t *lock);'
_Fortran_:
_Interface_: `subroutine omp_destroy_lock(lock)'
`integer(omp_lock_kind), intent(inout) :: lock'
_See also_:
*note omp_init_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.2.

File: libgomp.info, Node: omp_init_nest_lock, Next: omp_set_nest_lock, Prev: omp_destroy_lock, Up: Runtime Library Routines
2.26 `omp_init_nest_lock' - Initialize nested lock
==================================================
_Description_:
Initialize a nested lock. After initialization, the lock is in an
unlocked state and the nesting count is set to zero.
_C/C++_:
_Prototype_: `void omp_init_nest_lock(omp_nest_lock_t *lock);'
_Fortran_:
_Interface_: `subroutine omp_init_nest_lock(lock)'
`integer(omp_nest_lock_kind), intent(out) :: lock'
_See also_:
*note omp_destroy_nest_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.1.

File: libgomp.info, Node: omp_set_nest_lock, Next: omp_test_nest_lock, Prev: omp_init_nest_lock, Up: Runtime Library Routines
2.27 `omp_set_nest_lock' - Wait for and set nested lock
=======================================================
_Description_:
Before setting a nested lock, the lock variable must be
initialized by `omp_init_nest_lock'. The calling thread is blocked
until the lock is available. If the lock is already held by the
current thread, the nesting count for the lock is incremented.
_C/C++_:
_Prototype_: `void omp_set_nest_lock(omp_nest_lock_t *lock);'
_Fortran_:
_Interface_: `subroutine omp_set_nest_lock(lock)'
`integer(omp_nest_lock_kind), intent(inout) :: lock'
_See also_:
*note omp_init_nest_lock::, *note omp_unset_nest_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.3.

File: libgomp.info, Node: omp_test_nest_lock, Next: omp_unset_nest_lock, Prev: omp_set_nest_lock, Up: Runtime Library Routines
2.28 `omp_test_nest_lock' - Test and set nested lock if available
=================================================================
_Description_:
Before setting a nested lock, the lock variable must be
initialized by `omp_init_nest_lock'. Contrary to
`omp_set_nest_lock', `omp_test_nest_lock' does not block if the
lock is not available. If the lock is already held by the current
thread, the new nesting count is returned. Otherwise, the return
value equals zero.
_C/C++_:
_Prototype_: `int omp_test_nest_lock(omp_nest_lock_t *lock);'
_Fortran_:
_Interface_: `logical function omp_test_nest_lock(lock)'
`integer(omp_nest_lock_kind), intent(inout) :: lock'
_See also_:
*note omp_init_lock::, *note omp_set_lock::, *note omp_set_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.5.

File: libgomp.info, Node: omp_unset_nest_lock, Next: omp_destroy_nest_lock, Prev: omp_test_nest_lock, Up: Runtime Library Routines
2.29 `omp_unset_nest_lock' - Unset nested lock
==============================================
_Description_:
A nested lock about to be unset must have been locked by
`omp_set_nested_lock' or `omp_test_nested_lock' before. In
addition, the lock must be held by the thread calling
`omp_unset_nested_lock'. If the nesting count drops to zero, the
lock becomes unlocked. If one ore more threads attempted to set
the lock before, one of them is chosen to, again, set the lock to
itself.
_C/C++_:
_Prototype_: `void omp_unset_nest_lock(omp_nest_lock_t *lock);'
_Fortran_:
_Interface_: `subroutine omp_unset_nest_lock(lock)'
`integer(omp_nest_lock_kind), intent(inout) :: lock'
_See also_:
*note omp_set_nest_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.4.

File: libgomp.info, Node: omp_destroy_nest_lock, Next: omp_get_wtick, Prev: omp_unset_nest_lock, Up: Runtime Library Routines
2.30 `omp_destroy_nest_lock' - Destroy nested lock
==================================================
_Description_:
Destroy a nested lock. In order to be destroyed, a nested lock
must be in the unlocked state and its nesting count must equal
zero.
_C/C++_:
_Prototype_: `void omp_destroy_nest_lock(omp_nest_lock_t *);'
_Fortran_:
_Interface_: `subroutine omp_destroy_nest_lock(lock)'
`integer(omp_nest_lock_kind), intent(inout) :: lock'
_See also_:
*note omp_init_lock::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.3.2.

File: libgomp.info, Node: omp_get_wtick, Next: omp_get_wtime, Prev: omp_destroy_nest_lock, Up: Runtime Library Routines
2.31 `omp_get_wtick' - Get timer precision
==========================================
_Description_:
Gets the timer precision, i.e., the number of seconds between two
successive clock ticks.
_C/C++_:
_Prototype_: `double omp_get_wtick(void);'
_Fortran_:
_Interface_: `double precision function omp_get_wtick()'
_See also_:
*note omp_get_wtime::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.4.2.

File: libgomp.info, Node: omp_get_wtime, Prev: omp_get_wtick, Up: Runtime Library Routines
2.32 `omp_get_wtime' - Elapsed wall clock time
==============================================
_Description_:
Elapsed wall clock time in seconds. The time is measured per
thread, no guarantee can be made that two distinct threads measure
the same time. Time is measured from some "time in the past",
which is an arbitrary time guaranteed not to change during the
execution of the program.
_C/C++_:
_Prototype_: `double omp_get_wtime(void);'
_Fortran_:
_Interface_: `double precision function omp_get_wtime()'
_See also_:
*note omp_get_wtick::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 3.4.1.

File: libgomp.info, Node: Environment Variables, Next: The libgomp ABI, Prev: Runtime Library Routines, Up: Top
3 Environment Variables
***********************
The variables `OMP_DYNAMIC', `OMP_MAX_ACTIVE_LEVELS', `OMP_NESTED',
`OMP_NUM_THREADS', `OMP_SCHEDULE', `OMP_STACKSIZE',`OMP_THREAD_LIMIT'
and `OMP_WAIT_POLICY' are defined by section 4 of the OpenMP
specifications in version 3.1, while `GOMP_CPU_AFFINITY' and
`GOMP_STACKSIZE' are GNU extensions.
* Menu:
* OMP_DYNAMIC:: Dynamic adjustment of threads
* OMP_MAX_ACTIVE_LEVELS:: Set the maximum number of nested parallel regions
* OMP_NESTED:: Nested parallel regions
* OMP_NUM_THREADS:: Specifies the number of threads to use
* OMP_STACKSIZE:: Set default thread stack size
* OMP_SCHEDULE:: How threads are scheduled
* OMP_THREAD_LIMIT:: Set the maximum number of threads
* OMP_WAIT_POLICY:: How waiting threads are handled
* OMP_PROC_BIND:: Whether theads may be moved between CPUs
* GOMP_CPU_AFFINITY:: Bind threads to specific CPUs
* GOMP_STACKSIZE:: Set default thread stack size

File: libgomp.info, Node: OMP_DYNAMIC, Next: OMP_MAX_ACTIVE_LEVELS, Up: Environment Variables
3.1 `OMP_DYNAMIC' - Dynamic adjustment of threads
=================================================
_Description_:
Enable or disable the dynamic adjustment of the number of threads
within a team. The value of this environment variable shall be
`TRUE' or `FALSE'. If undefined, dynamic adjustment is disabled by
default.
_See also_:
*note omp_set_dynamic::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 4.3

File: libgomp.info, Node: OMP_MAX_ACTIVE_LEVELS, Next: OMP_NESTED, Prev: OMP_DYNAMIC, Up: Environment Variables
3.2 `OMP_MAX_ACTIVE_LEVELS' - Set the maximum number of nested parallel regions
===============================================================================
_Description_:
Specifies the initial value for the maximum number of nested
parallel regions. The value of this variable shall be a positive
integer. If undefined, the number of active levels is unlimited.
_See also_:
*note omp_set_max_active_levels::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 4.8

File: libgomp.info, Node: OMP_NESTED, Next: OMP_NUM_THREADS, Prev: OMP_MAX_ACTIVE_LEVELS, Up: Environment Variables
3.3 `OMP_NESTED' - Nested parallel regions
==========================================
_Description_:
Enable or disable nested parallel regions, i.e., whether team
members are allowed to create new teams. The value of this
environment variable shall be `TRUE' or `FALSE'. If undefined,
nested parallel regions are disabled by default.
_See also_:
*note omp_set_nested::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 4.5

File: libgomp.info, Node: OMP_NUM_THREADS, Next: OMP_STACKSIZE, Prev: OMP_NESTED, Up: Environment Variables
3.4 `OMP_NUM_THREADS' - Specifies the number of threads to use
==============================================================
_Description_:
Specifies the default number of threads to use in parallel
regions. The value of this variable shall be a comma-separated
list of positive integers; the value specified the number of
threads to use for the corresponding nested level. If undefined
one thread per CPU is used.
_See also_:
*note omp_set_num_threads::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 4.2

File: libgomp.info, Node: OMP_SCHEDULE, Next: OMP_THREAD_LIMIT, Prev: OMP_STACKSIZE, Up: Environment Variables
3.5 `OMP_SCHEDULE' - How threads are scheduled
==============================================
_Description_:
Allows to specify `schedule type' and `chunk size'. The value of
the variable shall have the form: `type[,chunk]' where `type' is
one of `static', `dynamic', `guided' or `auto' The optional
`chunk' size shall be a positive integer. If undefined, dynamic
scheduling and a chunk size of 1 is used.
_See also_:
*note omp_set_schedule::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), sections
2.5.1 and 4.1

File: libgomp.info, Node: OMP_STACKSIZE, Next: OMP_SCHEDULE, Prev: OMP_NUM_THREADS, Up: Environment Variables
3.6 `OMP_STACKSIZE' - Set default thread stack size
===================================================
_Description_:
Set the default thread stack size in kilobytes, unless the number
is suffixed by `B', `K', `M' or `G', in which case the size is,
respectively, in bytes, kilobytes, megabytes or gigabytes. This is
different from `pthread_attr_setstacksize' which gets the number
of bytes as an argument. If the stack size cannot be set due to
system constraints, an error is reported and the initial stack
size is left unchanged. If undefined, the stack size is system
dependent.
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), sections 4.6

File: libgomp.info, Node: OMP_THREAD_LIMIT, Next: OMP_WAIT_POLICY, Prev: OMP_SCHEDULE, Up: Environment Variables
3.7 `OMP_THREAD_LIMIT' - Set the maximum number of threads
==========================================================
_Description_:
Specifies the number of threads to use for the whole program. The
value of this variable shall be a positive integer. If undefined,
the number of threads is not limited.
_See also_:
*note OMP_NUM_THREADS:: *note omp_get_thread_limit::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), section 4.9

File: libgomp.info, Node: OMP_WAIT_POLICY, Next: OMP_PROC_BIND, Prev: OMP_THREAD_LIMIT, Up: Environment Variables
3.8 `OMP_WAIT_POLICY' - How waiting threads are handled
=======================================================
_Description_:
Specifies whether waiting threads should be active or passive. If
the value is `PASSIVE', waiting threads should not consume CPU
power while waiting; while the value is `ACTIVE' specifies that
they should.
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), sections 4.7

File: libgomp.info, Node: OMP_PROC_BIND, Next: GOMP_CPU_AFFINITY, Prev: OMP_WAIT_POLICY, Up: Environment Variables
3.9 `OMP_PROC_BIND' - Whether theads may be moved between CPUs
==============================================================
_Description_:
Specifies whether threads may be moved between processors. If set
to `true', OpenMP theads should not be moved, if set to `false'
they may be moved.
_See also_:
*note GOMP_CPU_AFFINITY::
_Reference_:
OpenMP specifications v3.1 (http://www.openmp.org/), sections 4.4

File: libgomp.info, Node: GOMP_CPU_AFFINITY, Next: GOMP_STACKSIZE, Prev: OMP_PROC_BIND, Up: Environment Variables
3.10 `GOMP_CPU_AFFINITY' - Bind threads to specific CPUs
========================================================
_Description_:
Binds threads to specific CPUs. The variable should contain a
space-separated or comma-separated list of CPUs. This list may
contain different kinds of entries: either single CPU numbers in
any order, a range of CPUs (M-N) or a range with some stride
(M-N:S). CPU numbers are zero based. For example,
`GOMP_CPU_AFFINITY="0 3 1-2 4-15:2"' will bind the initial thread
to CPU 0, the second to CPU 3, the third to CPU 1, the fourth to
CPU 2, the fifth to CPU 4, the sixth through tenth to CPUs 6, 8,
10, 12, and 14 respectively and then start assigning back from the
beginning of the list. `GOMP_CPU_AFFINITY=0' binds all threads to
CPU 0.
There is no GNU OpenMP library routine to determine whether a CPU
affinity specification is in effect. As a workaround,
language-specific library functions, e.g., `getenv' in C or
`GET_ENVIRONMENT_VARIABLE' in Fortran, may be used to query the
setting of the `GOMP_CPU_AFFINITY' environment variable. A defined
CPU affinity on startup cannot be changed or disabled during the
runtime of the application.
If this environment variable is omitted, the host system will
handle the assignment of threads to CPUs.
_See also_:
*note OMP_PROC_BIND::

File: libgomp.info, Node: GOMP_STACKSIZE, Prev: GOMP_CPU_AFFINITY, Up: Environment Variables
3.11 `GOMP_STACKSIZE' - Set default thread stack size
=====================================================
_Description_:
Set the default thread stack size in kilobytes. This is different
from `pthread_attr_setstacksize' which gets the number of bytes as
an argument. If the stack size cannot be set due to system
constraints, an error is reported and the initial stack size is
left unchanged. If undefined, the stack size is system dependent.
_See also_:
*note OMP_STACKSIZE::
_Reference_:
GCC Patches Mailinglist
(http://gcc.gnu.org/ml/gcc-patches/2006-06/msg00493.html), GCC
Patches Mailinglist
(http://gcc.gnu.org/ml/gcc-patches/2006-06/msg00496.html)

File: libgomp.info, Node: The libgomp ABI, Next: Reporting Bugs, Prev: Environment Variables, Up: Top
4 The libgomp ABI
*****************
The following sections present notes on the external ABI as presented
by libgomp. Only maintainers should need them.
* Menu:
* Implementing MASTER construct::
* Implementing CRITICAL construct::
* Implementing ATOMIC construct::
* Implementing FLUSH construct::
* Implementing BARRIER construct::
* Implementing THREADPRIVATE construct::
* Implementing PRIVATE clause::
* Implementing FIRSTPRIVATE LASTPRIVATE COPYIN and COPYPRIVATE clauses::
* Implementing REDUCTION clause::
* Implementing PARALLEL construct::
* Implementing FOR construct::
* Implementing ORDERED construct::
* Implementing SECTIONS construct::
* Implementing SINGLE construct::

File: libgomp.info, Node: Implementing MASTER construct, Next: Implementing CRITICAL construct, Up: The libgomp ABI
4.1 Implementing MASTER construct
=================================
if (omp_get_thread_num () == 0)
block
Alternately, we generate two copies of the parallel subfunction and
only include this in the version run by the master thread. Surely this
is not worthwhile though...

File: libgomp.info, Node: Implementing CRITICAL construct, Next: Implementing ATOMIC construct, Prev: Implementing MASTER construct, Up: The libgomp ABI
4.2 Implementing CRITICAL construct
===================================
Without a specified name,
void GOMP_critical_start (void);
void GOMP_critical_end (void);
so that we don't get COPY relocations from libgomp to the main
application.
With a specified name, use omp_set_lock and omp_unset_lock with name
being transformed into a variable declared like
omp_lock_t gomp_critical_user_<name> __attribute__((common))
Ideally the ABI would specify that all zero is a valid unlocked
state, and so we wouldn't need to initialize this at startup.

File: libgomp.info, Node: Implementing ATOMIC construct, Next: Implementing FLUSH construct, Prev: Implementing CRITICAL construct, Up: The libgomp ABI
4.3 Implementing ATOMIC construct
=================================
The target should implement the `__sync' builtins.
Failing that we could add
void GOMP_atomic_enter (void)
void GOMP_atomic_exit (void)
which reuses the regular lock code, but with yet another lock object
private to the library.

File: libgomp.info, Node: Implementing FLUSH construct, Next: Implementing BARRIER construct, Prev: Implementing ATOMIC construct, Up: The libgomp ABI
4.4 Implementing FLUSH construct
================================
Expands to the `__sync_synchronize' builtin.

File: libgomp.info, Node: Implementing BARRIER construct, Next: Implementing THREADPRIVATE construct, Prev: Implementing FLUSH construct, Up: The libgomp ABI
4.5 Implementing BARRIER construct
==================================
void GOMP_barrier (void)

File: libgomp.info, Node: Implementing THREADPRIVATE construct, Next: Implementing PRIVATE clause, Prev: Implementing BARRIER construct, Up: The libgomp ABI
4.6 Implementing THREADPRIVATE construct
========================================
In _most_ cases we can map this directly to `__thread'. Except that
OMP allows constructors for C++ objects. We can either refuse to
support this (how often is it used?) or we can implement something akin
to .ctors.
Even more ideally, this ctor feature is handled by extensions to the
main pthreads library. Failing that, we can have a set of entry points
to register ctor functions to be called.

File: libgomp.info, Node: Implementing PRIVATE clause, Next: Implementing FIRSTPRIVATE LASTPRIVATE COPYIN and COPYPRIVATE clauses, Prev: Implementing THREADPRIVATE construct, Up: The libgomp ABI
4.7 Implementing PRIVATE clause
===============================
In association with a PARALLEL, or within the lexical extent of a
PARALLEL block, the variable becomes a local variable in the parallel
subfunction.
In association with FOR or SECTIONS blocks, create a new automatic
variable within the current function. This preserves the semantic of
new variable creation.

File: libgomp.info, Node: Implementing FIRSTPRIVATE LASTPRIVATE COPYIN and COPYPRIVATE clauses, Next: Implementing REDUCTION clause, Prev: Implementing PRIVATE clause, Up: The libgomp ABI
4.8 Implementing FIRSTPRIVATE LASTPRIVATE COPYIN and COPYPRIVATE clauses
========================================================================
This seems simple enough for PARALLEL blocks. Create a private struct
for communicating between the parent and subfunction. In the parent,
copy in values for scalar and "small" structs; copy in addresses for
others TREE_ADDRESSABLE types. In the subfunction, copy the value into
the local variable.
It is not clear what to do with bare FOR or SECTION blocks. The
only thing I can figure is that we do something like:
#pragma omp for firstprivate(x) lastprivate(y)
for (int i = 0; i < n; ++i)
body;
which becomes
{
int x = x, y;
// for stuff
if (i == n)
y = y;
}
where the "x=x" and "y=y" assignments actually have different uids
for the two variables, i.e. not something you could write directly in
C. Presumably this only makes sense if the "outer" x and y are global
variables.
COPYPRIVATE would work the same way, except the structure broadcast
would have to happen via SINGLE machinery instead.

File: libgomp.info, Node: Implementing REDUCTION clause, Next: Implementing PARALLEL construct, Prev: Implementing FIRSTPRIVATE LASTPRIVATE COPYIN and COPYPRIVATE clauses, Up: The libgomp ABI
4.9 Implementing REDUCTION clause
=================================
The private struct mentioned in the previous section should have a
pointer to an array of the type of the variable, indexed by the
thread's TEAM_ID. The thread stores its final value into the array,
and after the barrier, the master thread iterates over the array to
collect the values.

File: libgomp.info, Node: Implementing PARALLEL construct, Next: Implementing FOR construct, Prev: Implementing REDUCTION clause, Up: The libgomp ABI
4.10 Implementing PARALLEL construct
====================================
#pragma omp parallel
{
body;
}
becomes
void subfunction (void *data)
{
use data;
body;
}
setup data;
GOMP_parallel_start (subfunction, &data, num_threads);
subfunction (&data);
GOMP_parallel_end ();
void GOMP_parallel_start (void (*fn)(void *), void *data, unsigned num_threads)
The FN argument is the subfunction to be run in parallel.
The DATA argument is a pointer to a structure used to communicate
data in and out of the subfunction, as discussed above with respect to
FIRSTPRIVATE et al.
The NUM_THREADS argument is 1 if an IF clause is present and false,
or the value of the NUM_THREADS clause, if present, or 0.
The function needs to create the appropriate number of threads
and/or launch them from the dock. It needs to create the team
structure and assign team ids.
void GOMP_parallel_end (void)
Tears down the team and returns us to the previous
`omp_in_parallel()' state.

File: libgomp.info, Node: Implementing FOR construct, Next: Implementing ORDERED construct, Prev: Implementing PARALLEL construct, Up: The libgomp ABI
4.11 Implementing FOR construct
===============================
#pragma omp parallel for
for (i = lb; i <= ub; i++)
body;
becomes
void subfunction (void *data)
{
long _s0, _e0;
while (GOMP_loop_static_next (&_s0, &_e0))
{
long _e1 = _e0, i;
for (i = _s0; i < _e1; i++)
body;
}
GOMP_loop_end_nowait ();
}
GOMP_parallel_loop_static (subfunction, NULL, 0, lb, ub+1, 1, 0);
subfunction (NULL);
GOMP_parallel_end ();
#pragma omp for schedule(runtime)
for (i = 0; i < n; i++)
body;
becomes
{
long i, _s0, _e0;
if (GOMP_loop_runtime_start (0, n, 1, &_s0, &_e0))
do {
long _e1 = _e0;
for (i = _s0, i < _e0; i++)
body;
} while (GOMP_loop_runtime_next (&_s0, _&e0));
GOMP_loop_end ();
}
Note that while it looks like there is trickiness to propagating a
non-constant STEP, there isn't really. We're explicitly allowed to
evaluate it as many times as we want, and any variables involved should
automatically be handled as PRIVATE or SHARED like any other variables.
So the expression should remain evaluable in the subfunction. We can
also pull it into a local variable if we like, but since its supposed
to remain unchanged, we can also not if we like.
If we have SCHEDULE(STATIC), and no ORDERED, then we ought to be
able to get away with no work-sharing context at all, since we can
simply perform the arithmetic directly in each thread to divide up the
iterations. Which would mean that we wouldn't need to call any of
these routines.
There are separate routines for handling loops with an ORDERED
clause. Bookkeeping for that is non-trivial...

File: libgomp.info, Node: Implementing ORDERED construct, Next: Implementing SECTIONS construct, Prev: Implementing FOR construct, Up: The libgomp ABI
4.12 Implementing ORDERED construct
===================================
void GOMP_ordered_start (void)
void GOMP_ordered_end (void)

File: libgomp.info, Node: Implementing SECTIONS construct, Next: Implementing SINGLE construct, Prev: Implementing ORDERED construct, Up: The libgomp ABI
4.13 Implementing SECTIONS construct
====================================
A block as
#pragma omp sections
{
#pragma omp section
stmt1;
#pragma omp section
stmt2;
#pragma omp section
stmt3;
}
becomes
for (i = GOMP_sections_start (3); i != 0; i = GOMP_sections_next ())
switch (i)
{
case 1:
stmt1;
break;
case 2:
stmt2;
break;
case 3:
stmt3;
break;
}
GOMP_barrier ();

File: libgomp.info, Node: Implementing SINGLE construct, Prev: Implementing SECTIONS construct, Up: The libgomp ABI
4.14 Implementing SINGLE construct
==================================
A block like
#pragma omp single
{
body;
}
becomes
if (GOMP_single_start ())
body;
GOMP_barrier ();
while
#pragma omp single copyprivate(x)
body;
becomes
datap = GOMP_single_copy_start ();
if (datap == NULL)
{
body;
data.x = x;
GOMP_single_copy_end (&data);
}
else
x = datap->x;
GOMP_barrier ();

File: libgomp.info, Node: Reporting Bugs, Next: Copying, Prev: The libgomp ABI, Up: Top
5 Reporting Bugs
****************
Bugs in the GNU OpenMP implementation should be reported via bugzilla
(http://gcc.gnu.org/bugzilla/). For all cases, please add "openmp" to
the keywords field in the bug report.

File: libgomp.info, Node: Copying, Next: GNU Free Documentation License, Prev: Reporting Bugs, Up: Top
GNU General Public License
**************************
Version 3, 29 June 2007
Copyright (C) 2007 Free Software Foundation, Inc. `http://fsf.org/'
Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.
Preamble
========
The GNU General Public License is a free, copyleft license for software
and other kinds of works.
The licenses for most software and other practical works are designed
to take away your freedom to share and change the works. By contrast,
the GNU General Public License is intended to guarantee your freedom to
share and change all versions of a program-to make sure it remains free
software for all its users. We, the Free Software Foundation, use the
GNU General Public License for most of our software; it applies also to
any other work released this way by its authors. You can apply it to
your programs, too.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
them if you wish), that you receive source code or can get it if you
want it, that you can change the software or use pieces of it in new
free programs, and that you know you can do these things.
To protect your rights, we need to prevent others from denying you
these rights or asking you to surrender the rights. Therefore, you
have certain responsibilities if you distribute copies of the software,
or if you modify it: responsibilities to respect the freedom of others.
For example, if you distribute copies of such a program, whether
gratis or for a fee, you must pass on to the recipients the same
freedoms that you received. You must make sure that they, too, receive
or can get the source code. And you must show them these terms so they
know their rights.
Developers that use the GNU GPL protect your rights with two steps:
(1) assert copyright on the software, and (2) offer you this License
giving you legal permission to copy, distribute and/or modify it.
For the developers' and authors' protection, the GPL clearly explains
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authors' sake, the GPL requires that modified versions be marked as
changed, so that their problems will not be attributed erroneously to
authors of previous versions.
Some devices are designed to deny users access to install or run
modified versions of the software inside them, although the
manufacturer can do so. This is fundamentally incompatible with the
aim of protecting users' freedom to change the software. The
systematic pattern of such abuse occurs in the area of products for
individuals to use, which is precisely where it is most unacceptable.
Therefore, we have designed this version of the GPL to prohibit the
practice for those products. If such problems arise substantially in
other domains, we stand ready to extend this provision to those domains
in future versions of the GPL, as needed to protect the freedom of
users.
Finally, every program is threatened constantly by software patents.
States should not allow patents to restrict development and use of
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avoid the special danger that patents applied to a free program could
make it effectively proprietary. To prevent this, the GPL assures that
patents cannot be used to render the program non-free.
The precise terms and conditions for copying, distribution and
modification follow.
TERMS AND CONDITIONS
====================
0. Definitions.
"This License" refers to version 3 of the GNU General Public
License.
"Copyright" also means copyright-like laws that apply to other
kinds of works, such as semiconductor masks.
"The Program" refers to any copyrightable work licensed under this
License. Each licensee is addressed as "you". "Licensees" and
"recipients" may be individuals or organizations.
To "modify" a work means to copy from or adapt all or part of the
work in a fashion requiring copyright permission, other than the
making of an exact copy. The resulting work is called a "modified
version" of the earlier work or a work "based on" the earlier work.
A "covered work" means either the unmodified Program or a work
based on the Program.
To "propagate" a work means to do anything with it that, without
permission, would make you directly or secondarily liable for
infringement under applicable copyright law, except executing it
on a computer or modifying a private copy. Propagation includes
copying, distribution (with or without modification), making
available to the public, and in some countries other activities as
well.
To "convey" a work means any kind of propagation that enables other
parties to make or receive copies. Mere interaction with a user
through a computer network, with no transfer of a copy, is not
conveying.
An interactive user interface displays "Appropriate Legal Notices"
to the extent that it includes a convenient and prominently visible
feature that (1) displays an appropriate copyright notice, and (2)
tells the user that there is no warranty for the work (except to
the extent that warranties are provided), that licensees may
convey the work under this License, and how to view a copy of this
License. If the interface presents a list of user commands or
options, such as a menu, a prominent item in the list meets this
criterion.
1. Source Code.
The "source code" for a work means the preferred form of the work
for making modifications to it. "Object code" means any
non-source form of a work.
A "Standard Interface" means an interface that either is an
official standard defined by a recognized standards body, or, in
the case of interfaces specified for a particular programming
language, one that is widely used among developers working in that
language.
The "System Libraries" of an executable work include anything,
other than the work as a whole, that (a) is included in the normal
form of packaging a Major Component, but which is not part of that
Major Component, and (b) serves only to enable use of the work
with that Major Component, or to implement a Standard Interface
for which an implementation is available to the public in source
code form. A "Major Component", in this context, means a major
essential component (kernel, window system, and so on) of the
specific operating system (if any) on which the executable work
runs, or a compiler used to produce the work, or an object code
interpreter used to run it.
The "Corresponding Source" for a work in object code form means all
the source code needed to generate, install, and (for an executable
work) run the object code and to modify the work, including
scripts to control those activities. However, it does not include
the work's System Libraries, or general-purpose tools or generally
available free programs which are used unmodified in performing
those activities but which are not part of the work. For example,
Corresponding Source includes interface definition files
associated with source files for the work, and the source code for
shared libraries and dynamically linked subprograms that the work
is specifically designed to require, such as by intimate data
communication or control flow between those subprograms and other
parts of the work.
The Corresponding Source need not include anything that users can
regenerate automatically from other parts of the Corresponding
Source.
The Corresponding Source for a work in source code form is that
same work.
2. Basic Permissions.
All rights granted under this License are granted for the term of
copyright on the Program, and are irrevocable provided the stated
conditions are met. This License explicitly affirms your unlimited
permission to run the unmodified Program. The output from running
a covered work is covered by this License only if the output,
given its content, constitutes a covered work. This License
acknowledges your rights of fair use or other equivalent, as
provided by copyright law.
You may make, run and propagate covered works that you do not
convey, without conditions so long as your license otherwise
remains in force. You may convey covered works to others for the
sole purpose of having them make modifications exclusively for
you, or provide you with facilities for running those works,
provided that you comply with the terms of this License in
conveying all material for which you do not control copyright.
Those thus making or running the covered works for you must do so
exclusively on your behalf, under your direction and control, on
terms that prohibit them from making any copies of your
copyrighted material outside their relationship with you.
Conveying under any other circumstances is permitted solely under
the conditions stated below. Sublicensing is not allowed; section
10 makes it unnecessary.
3. Protecting Users' Legal Rights From Anti-Circumvention Law.
No covered work shall be deemed part of an effective technological
measure under any applicable law fulfilling obligations under
article 11 of the WIPO copyright treaty adopted on 20 December
1996, or similar laws prohibiting or restricting circumvention of
such measures.
When you convey a covered work, you waive any legal power to forbid
circumvention of technological measures to the extent such
circumvention is effected by exercising rights under this License
with respect to the covered work, and you disclaim any intention
to limit operation or modification of the work as a means of
enforcing, against the work's users, your or third parties' legal
rights to forbid circumvention of technological measures.
4. Conveying Verbatim Copies.
You may convey verbatim copies of the Program's source code as you
receive it, in any medium, provided that you conspicuously and
appropriately publish on each copy an appropriate copyright notice;
keep intact all notices stating that this License and any
non-permissive terms added in accord with section 7 apply to the
code; keep intact all notices of the absence of any warranty; and
give all recipients a copy of this License along with the Program.
You may charge any price or no price for each copy that you convey,
and you may offer support or warranty protection for a fee.
5. Conveying Modified Source Versions.
You may convey a work based on the Program, or the modifications to
produce it from the Program, in the form of source code under the
terms of section 4, provided that you also meet all of these
conditions:
a. The work must carry prominent notices stating that you
modified it, and giving a relevant date.
b. The work must carry prominent notices stating that it is
released under this License and any conditions added under
section 7. This requirement modifies the requirement in
section 4 to "keep intact all notices".
c. You must license the entire work, as a whole, under this
License to anyone who comes into possession of a copy. This
License will therefore apply, along with any applicable
section 7 additional terms, to the whole of the work, and all
its parts, regardless of how they are packaged. This License
gives no permission to license the work in any other way, but
it does not invalidate such permission if you have separately
received it.
d. If the work has interactive user interfaces, each must display
Appropriate Legal Notices; however, if the Program has
interactive interfaces that do not display Appropriate Legal
Notices, your work need not make them do so.
A compilation of a covered work with other separate and independent
works, which are not by their nature extensions of the covered
work, and which are not combined with it such as to form a larger
program, in or on a volume of a storage or distribution medium, is
called an "aggregate" if the compilation and its resulting
copyright are not used to limit the access or legal rights of the
compilation's users beyond what the individual works permit.
Inclusion of a covered work in an aggregate does not cause this
License to apply to the other parts of the aggregate.
6. Conveying Non-Source Forms.
You may convey a covered work in object code form under the terms
of sections 4 and 5, provided that you also convey the
machine-readable Corresponding Source under the terms of this
License, in one of these ways:
a. Convey the object code in, or embodied in, a physical product
(including a physical distribution medium), accompanied by the
Corresponding Source fixed on a durable physical medium
customarily used for software interchange.
b. Convey the object code in, or embodied in, a physical product
(including a physical distribution medium), accompanied by a
written offer, valid for at least three years and valid for
as long as you offer spare parts or customer support for that
product model, to give anyone who possesses the object code
either (1) a copy of the Corresponding Source for all the
software in the product that is covered by this License, on a
durable physical medium customarily used for software
interchange, for a price no more than your reasonable cost of
physically performing this conveying of source, or (2) access
to copy the Corresponding Source from a network server at no
charge.
c. Convey individual copies of the object code with a copy of
the written offer to provide the Corresponding Source. This
alternative is allowed only occasionally and noncommercially,
and only if you received the object code with such an offer,
in accord with subsection 6b.
d. Convey the object code by offering access from a designated
place (gratis or for a charge), and offer equivalent access
to the Corresponding Source in the same way through the same
place at no further charge. You need not require recipients
to copy the Corresponding Source along with the object code.
If the place to copy the object code is a network server, the
Corresponding Source may be on a different server (operated
by you or a third party) that supports equivalent copying
facilities, provided you maintain clear directions next to
the object code saying where to find the Corresponding Source.
Regardless of what server hosts the Corresponding Source, you
remain obligated to ensure that it is available for as long
as needed to satisfy these requirements.
e. Convey the object code using peer-to-peer transmission,
provided you inform other peers where the object code and
Corresponding Source of the work are being offered to the
general public at no charge under subsection 6d.
A separable portion of the object code, whose source code is
excluded from the Corresponding Source as a System Library, need
not be included in conveying the object code work.
A "User Product" is either (1) a "consumer product", which means
any tangible personal property which is normally used for personal,
family, or household purposes, or (2) anything designed or sold for
incorporation into a dwelling. In determining whether a product
is a consumer product, doubtful cases shall be resolved in favor of
coverage. For a particular product received by a particular user,
"normally used" refers to a typical or common use of that class of
product, regardless of the status of the particular user or of the
way in which the particular user actually uses, or expects or is
expected to use, the product. A product is a consumer product
regardless of whether the product has substantial commercial,
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"Installation Information" for a User Product means any methods,
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The information must suffice to ensure that the continued
functioning of the modified object code is in no case prevented or
interfered with solely because modification has been made.
If you convey an object code work under this section in, or with,
or specifically for use in, a User Product, and the conveying
occurs as part of a transaction in which the right of possession
and use of the User Product is transferred to the recipient in
perpetuity or for a fixed term (regardless of how the transaction
is characterized), the Corresponding Source conveyed under this
section must be accompanied by the Installation Information. But
this requirement does not apply if neither you nor any third party
retains the ability to install modified object code on the User
Product (for example, the work has been installed in ROM).
The requirement to provide Installation Information does not
include a requirement to continue to provide support service,
warranty, or updates for a work that has been modified or
installed by the recipient, or for the User Product in which it
has been modified or installed. Access to a network may be denied
when the modification itself materially and adversely affects the
operation of the network or violates the rules and protocols for
communication across the network.
Corresponding Source conveyed, and Installation Information
provided, in accord with this section must be in a format that is
publicly documented (and with an implementation available to the
public in source code form), and must require no special password
or key for unpacking, reading or copying.
7. Additional Terms.
"Additional permissions" are terms that supplement the terms of
this License by making exceptions from one or more of its
conditions. Additional permissions that are applicable to the
entire Program shall be treated as though they were included in
this License, to the extent that they are valid under applicable
law. If additional permissions apply only to part of the Program,
that part may be used separately under those permissions, but the
entire Program remains governed by this License without regard to
the additional permissions.
When you convey a copy of a covered work, you may at your option
remove any additional permissions from that copy, or from any part
of it. (Additional permissions may be written to require their own
removal in certain cases when you modify the work.) You may place
additional permissions on material, added by you to a covered work,
for which you have or can give appropriate copyright permission.
Notwithstanding any other provision of this License, for material
you add to a covered work, you may (if authorized by the copyright
holders of that material) supplement the terms of this License
with terms:
a. Disclaiming warranty or limiting liability differently from
the terms of sections 15 and 16 of this License; or
b. Requiring preservation of specified reasonable legal notices
or author attributions in that material or in the Appropriate
Legal Notices displayed by works containing it; or
c. Prohibiting misrepresentation of the origin of that material,
or requiring that modified versions of such material be
marked in reasonable ways as different from the original
version; or
d. Limiting the use for publicity purposes of names of licensors
or authors of the material; or
e. Declining to grant rights under trademark law for use of some
trade names, trademarks, or service marks; or
f. Requiring indemnification of licensors and authors of that
material by anyone who conveys the material (or modified
versions of it) with contractual assumptions of liability to
the recipient, for any liability that these contractual
assumptions directly impose on those licensors and authors.
All other non-permissive additional terms are considered "further
restrictions" within the meaning of section 10. If the Program as
you received it, or any part of it, contains a notice stating that
it is governed by this License along with a term that is a further
restriction, you may remove that term. If a license document
contains a further restriction but permits relicensing or
conveying under this License, you may add to a covered work
material governed by the terms of that license document, provided
that the further restriction does not survive such relicensing or
conveying.
If you add terms to a covered work in accord with this section, you
must place, in the relevant source files, a statement of the
additional terms that apply to those files, or a notice indicating
where to find the applicable terms.
Additional terms, permissive or non-permissive, may be stated in
the form of a separately written license, or stated as exceptions;
the above requirements apply either way.
8. Termination.
You may not propagate or modify a covered work except as expressly
provided under this License. Any attempt otherwise to propagate or
modify it is void, and will automatically terminate your rights
under this License (including any patent licenses granted under
the third paragraph of section 11).
However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly
and finally terminates your license, and (b) permanently, if the
copyright holder fails to notify you of the violation by some
reasonable means prior to 60 days after the cessation.
Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from
that copyright holder, and you cure the violation prior to 30 days
after your receipt of the notice.
Termination of your rights under this section does not terminate
the licenses of parties who have received copies or rights from
you under this License. If your rights have been terminated and
not permanently reinstated, you do not qualify to receive new
licenses for the same material under section 10.
9. Acceptance Not Required for Having Copies.
You are not required to accept this License in order to receive or
run a copy of the Program. Ancillary propagation of a covered work
occurring solely as a consequence of using peer-to-peer
transmission to receive a copy likewise does not require
acceptance. However, nothing other than this License grants you
permission to propagate or modify any covered work. These actions
infringe copyright if you do not accept this License. Therefore,
by modifying or propagating a covered work, you indicate your
acceptance of this License to do so.
10. Automatic Licensing of Downstream Recipients.
Each time you convey a covered work, the recipient automatically
receives a license from the original licensors, to run, modify and
propagate that work, subject to this License. You are not
responsible for enforcing compliance by third parties with this
License.
An "entity transaction" is a transaction transferring control of an
organization, or substantially all assets of one, or subdividing an
organization, or merging organizations. If propagation of a
covered work results from an entity transaction, each party to that
transaction who receives a copy of the work also receives whatever
licenses to the work the party's predecessor in interest had or
could give under the previous paragraph, plus a right to
possession of the Corresponding Source of the work from the
predecessor in interest, if the predecessor has it or can get it
with reasonable efforts.
You may not impose any further restrictions on the exercise of the
rights granted or affirmed under this License. For example, you
may not impose a license fee, royalty, or other charge for
exercise of rights granted under this License, and you may not
initiate litigation (including a cross-claim or counterclaim in a
lawsuit) alleging that any patent claim is infringed by making,
using, selling, offering for sale, or importing the Program or any
portion of it.
11. Patents.
A "contributor" is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based.
The work thus licensed is called the contributor's "contributor
version".
A contributor's "essential patent claims" are all patent claims
owned or controlled by the contributor, whether already acquired or
hereafter acquired, that would be infringed by some manner,
permitted by this License, of making, using, or selling its
contributor version, but do not include claims that would be
infringed only as a consequence of further modification of the
contributor version. For purposes of this definition, "control"
includes the right to grant patent sublicenses in a manner
consistent with the requirements of this License.
Each contributor grants you a non-exclusive, worldwide,
royalty-free patent license under the contributor's essential
patent claims, to make, use, sell, offer for sale, import and
otherwise run, modify and propagate the contents of its
contributor version.
In the following three paragraphs, a "patent license" is any
express agreement or commitment, however denominated, not to
enforce a patent (such as an express permission to practice a
patent or covenant not to sue for patent infringement). To
"grant" such a patent license to a party means to make such an
agreement or commitment not to enforce a patent against the party.
If you convey a covered work, knowingly relying on a patent
license, and the Corresponding Source of the work is not available
for anyone to copy, free of charge and under the terms of this
License, through a publicly available network server or other
readily accessible means, then you must either (1) cause the
Corresponding Source to be so available, or (2) arrange to deprive
yourself of the benefit of the patent license for this particular
work, or (3) arrange, in a manner consistent with the requirements
of this License, to extend the patent license to downstream
recipients. "Knowingly relying" means you have actual knowledge
that, but for the patent license, your conveying the covered work
in a country, or your recipient's use of the covered work in a
country, would infringe one or more identifiable patents in that
country that you have reason to believe are valid.
If, pursuant to or in connection with a single transaction or
arrangement, you convey, or propagate by procuring conveyance of, a
covered work, and grant a patent license to some of the parties
receiving the covered work authorizing them to use, propagate,
modify or convey a specific copy of the covered work, then the
patent license you grant is automatically extended to all
recipients of the covered work and works based on it.
A patent license is "discriminatory" if it does not include within
the scope of its coverage, prohibits the exercise of, or is
conditioned on the non-exercise of one or more of the rights that
are specifically granted under this License. You may not convey a
covered work if you are a party to an arrangement with a third
party that is in the business of distributing software, under
which you make payment to the third party based on the extent of
your activity of conveying the work, and under which the third
party grants, to any of the parties who would receive the covered
work from you, a discriminatory patent license (a) in connection
with copies of the covered work conveyed by you (or copies made
from those copies), or (b) primarily for and in connection with
specific products or compilations that contain the covered work,
unless you entered into that arrangement, or that patent license
was granted, prior to 28 March 2007.
Nothing in this License shall be construed as excluding or limiting
any implied license or other defenses to infringement that may
otherwise be available to you under applicable patent law.
12. No Surrender of Others' Freedom.
If conditions are imposed on you (whether by court order,
agreement or otherwise) that contradict the conditions of this
License, they do not excuse you from the conditions of this
License. If you cannot convey a covered work so as to satisfy
simultaneously your obligations under this License and any other
pertinent obligations, then as a consequence you may not convey it
at all. For example, if you agree to terms that obligate you to
collect a royalty for further conveying from those to whom you
convey the Program, the only way you could satisfy both those
terms and this License would be to refrain entirely from conveying
the Program.
13. Use with the GNU Affero General Public License.
Notwithstanding any other provision of this License, you have
permission to link or combine any covered work with a work licensed
under version 3 of the GNU Affero General Public License into a
single combined work, and to convey the resulting work. The terms
of this License will continue to apply to the part which is the
covered work, but the special requirements of the GNU Affero
General Public License, section 13, concerning interaction through
a network will apply to the combination as such.
14. Revised Versions of this License.
The Free Software Foundation may publish revised and/or new
versions of the GNU General Public License from time to time.
Such new versions will be similar in spirit to the present
version, but may differ in detail to address new problems or
concerns.
Each version is given a distinguishing version number. If the
Program specifies that a certain numbered version of the GNU
General Public License "or any later version" applies to it, you
have the option of following the terms and conditions either of
that numbered version or of any later version published by the
Free Software Foundation. If the Program does not specify a
version number of the GNU General Public License, you may choose
any version ever published by the Free Software Foundation.
If the Program specifies that a proxy can decide which future
versions of the GNU General Public License can be used, that
proxy's public statement of acceptance of a version permanently
authorizes you to choose that version for the Program.
Later license versions may give you additional or different
permissions. However, no additional obligations are imposed on any
author or copyright holder as a result of your choosing to follow a
later version.
15. Disclaimer of Warranty.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE
COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE
RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.
SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR OR CORRECTION.
16. Limitation of Liability.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES
AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU
FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA
BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF
THE POSSIBILITY OF SUCH DAMAGES.
17. Interpretation of Sections 15 and 16.
If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely
approximates an absolute waiver of all civil liability in
connection with the Program, unless a warranty or assumption of
liability accompanies a copy of the Program in return for a fee.
END OF TERMS AND CONDITIONS
===========================
How to Apply These Terms to Your New Programs
=============================================
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these
terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least the
"copyright" line and a pointer to where the full notice is found.
ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES.
Copyright (C) YEAR NAME OF AUTHOR
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see `http://www.gnu.org/licenses/'.
Also add information on how to contact you by electronic and paper
mail.
If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:
PROGRAM Copyright (C) YEAR NAME OF AUTHOR
This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show the
appropriate parts of the General Public License. Of course, your
program's commands might be different; for a GUI interface, you would
use an "about box".
You should also get your employer (if you work as a programmer) or
school, if any, to sign a "copyright disclaimer" for the program, if
necessary. For more information on this, and how to apply and follow
the GNU GPL, see `http://www.gnu.org/licenses/'.
The GNU General Public License does not permit incorporating your
program into proprietary programs. If your program is a subroutine
library, you may consider it more useful to permit linking proprietary
applications with the library. If this is what you want to do, use the
GNU Lesser General Public License instead of this License. But first,
please read `http://www.gnu.org/philosophy/why-not-lgpl.html'.

File: libgomp.info, Node: GNU Free Documentation License, Next: Funding, Prev: Copying, Up: Top
GNU Free Documentation License
******************************
Version 1.3, 3 November 2008
Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
`http://fsf.org/'
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
functional and useful document "free" in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not
being considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense.
It complements the GNU General Public License, which is a copyleft
license designed for free software.
We have designed this License in order to use it for manuals for
free software, because free software needs free documentation: a
free program should come with manuals providing the same freedoms
that the software does. But this License is not limited to
software manuals; it can be used for any textual work, regardless
of subject matter or whether it is published as a printed book.
We recommend this License principally for works whose purpose is
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1. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium,
that contains a notice placed by the copyright holder saying it
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The "Cover Texts" are certain short passages of text that are
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The "Title Page" means, for a printed book, the title page itself,
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To "Preserve the Title" of such a section when you modify the
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The Document may include Warranty Disclaimers next to the notice
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You may copy and distribute the Document in any medium, either
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If you publish printed copies (or copies in media that commonly
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It is requested, but not required, that you contact the authors of
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4. MODIFICATIONS
You may copy and distribute a Modified Version of the Document
under the conditions of sections 2 and 3 above, provided that you
release the Modified Version under precisely this License, with
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licensing distribution and modification of the Modified Version to
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things in the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title
distinct from that of the Document, and from those of
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same title as a previous version if the original publisher of
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B. List on the Title Page, as authors, one or more persons or
entities responsible for authorship of the modifications in
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principal authors of the Document (all of its principal
authors, if it has fewer than five), unless they release you
from this requirement.
C. State on the Title page the name of the publisher of the
Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license
notice giving the public permission to use the Modified
Version under the terms of this License, in the form shown in
the Addendum below.
G. Preserve in that license notice the full lists of Invariant
Sections and required Cover Texts given in the Document's
license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled "History", Preserve its Title,
and add to it an item stating at least the title, year, new
authors, and publisher of the Modified Version as given on
the Title Page. If there is no section Entitled "History" in
the Document, create one stating the title, year, authors,
and publisher of the Document as given on its Title Page,
then add an item describing the Modified Version as stated in
the previous sentence.
J. Preserve the network location, if any, given in the Document
for public access to a Transparent copy of the Document, and
likewise the network locations given in the Document for
previous versions it was based on. These may be placed in
the "History" section. You may omit a network location for a
work that was published at least four years before the
Document itself, or if the original publisher of the version
it refers to gives permission.
K. For any section Entitled "Acknowledgements" or "Dedications",
Preserve the Title of the section, and preserve in the
section all the substance and tone of each of the contributor
acknowledgements and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document,
unaltered in their text and in their titles. Section numbers
or the equivalent are not considered part of the section
titles.
M. Delete any section Entitled "Endorsements". Such a section
may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled
"Endorsements" or to conflict in title with any Invariant
Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no
material copied from the Document, you may at your option
designate some or all of these sections as invariant. To do this,
add their titles to the list of Invariant Sections in the Modified
Version's license notice. These titles must be distinct from any
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You may add a section Entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text
has been approved by an organization as the authoritative
definition of a standard.
You may add a passage of up to five words as a Front-Cover Text,
and a passage of up to 25 words as a Back-Cover Text, to the end
of the list of Cover Texts in the Modified Version. Only one
passage of Front-Cover Text and one of Back-Cover Text may be
added by (or through arrangements made by) any one entity. If the
Document already includes a cover text for the same cover,
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The author(s) and publisher(s) of the Document do not by this
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assert or imply endorsement of any Modified Version.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under
this License, under the terms defined in section 4 above for
modified versions, provided that you include in the combination
all of the Invariant Sections of all of the original documents,
unmodified, and list them all as Invariant Sections of your
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their Warranty Disclaimers.
The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy. If there are multiple Invariant Sections with the same name
but different contents, make the title of each such section unique
by adding at the end of it, in parentheses, the name of the
original author or publisher of that section if known, or else a
unique number. Make the same adjustment to the section titles in
the list of Invariant Sections in the license notice of the
combined work.
In the combination, you must combine any sections Entitled
"History" in the various original documents, forming one section
Entitled "History"; likewise combine any sections Entitled
"Acknowledgements", and any sections Entitled "Dedications". You
must delete all sections Entitled "Endorsements."
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other
documents released under this License, and replace the individual
copies of this License in the various documents with a single copy
that is included in the collection, provided that you follow the
rules of this License for verbatim copying of each of the
documents in all other respects.
You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert
a copy of this License into the extracted document, and follow
this License in all other respects regarding verbatim copying of
that document.
7. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other
separate and independent documents or works, in or on a volume of
a storage or distribution medium, is called an "aggregate" if the
copyright resulting from the compilation is not used to limit the
legal rights of the compilation's users beyond what the individual
works permit. When the Document is included in an aggregate, this
License does not apply to the other works in the aggregate which
are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half
of the entire aggregate, the Document's Cover Texts may be placed
on covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic
form. Otherwise they must appear on printed covers that bracket
the whole aggregate.
8. TRANSLATION
Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section
4. Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections. You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also
include the original English version of this License and the
original versions of those notices and disclaimers. In case of a
disagreement between the translation and the original version of
this License or a notice or disclaimer, the original version will
prevail.
If a section in the Document is Entitled "Acknowledgements",
"Dedications", or "History", the requirement (section 4) to
Preserve its Title (section 1) will typically require changing the
actual title.
9. TERMINATION
You may not copy, modify, sublicense, or distribute the Document
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense, or distribute it is void,
and will automatically terminate your rights under this License.
However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly
and finally terminates your license, and (b) permanently, if the
copyright holder fails to notify you of the violation by some
reasonable means prior to 60 days after the cessation.
Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from
that copyright holder, and you cure the violation prior to 30 days
after your receipt of the notice.
Termination of your rights under this section does not terminate
the licenses of parties who have received copies or rights from
you under this License. If your rights have been terminated and
not permanently reinstated, receipt of a copy of some or all of
the same material does not give you any rights to use it.
10. FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of
the GNU Free Documentation License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns. See
`http://www.gnu.org/copyleft/'.
Each version of the License is given a distinguishing version
number. If the Document specifies that a particular numbered
version of this License "or any later version" applies to it, you
have the option of following the terms and conditions either of
that specified version or of any later version that has been
published (not as a draft) by the Free Software Foundation. If
the Document does not specify a version number of this License,
you may choose any version ever published (not as a draft) by the
Free Software Foundation. If the Document specifies that a proxy
can decide which future versions of this License can be used, that
proxy's public statement of acceptance of a version permanently
authorizes you to choose that version for the Document.
11. RELICENSING
"Massive Multiauthor Collaboration Site" (or "MMC Site") means any
World Wide Web server that publishes copyrightable works and also
provides prominent facilities for anybody to edit those works. A
public wiki that anybody can edit is an example of such a server.
A "Massive Multiauthor Collaboration" (or "MMC") contained in the
site means any set of copyrightable works thus published on the MMC
site.
"CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0
license published by Creative Commons Corporation, a not-for-profit
corporation with a principal place of business in San Francisco,
California, as well as future copyleft versions of that license
published by that same organization.
"Incorporate" means to publish or republish a Document, in whole or
in part, as part of another Document.
An MMC is "eligible for relicensing" if it is licensed under this
License, and if all works that were first published under this
License somewhere other than this MMC, and subsequently
incorporated in whole or in part into the MMC, (1) had no cover
texts or invariant sections, and (2) were thus incorporated prior
to November 1, 2008.
The operator of an MMC Site may republish an MMC contained in the
site under CC-BY-SA on the same site at any time before August 1,
2009, provided the MMC is eligible for relicensing.
ADDENDUM: How to use this License for your documents
====================================================
To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:
Copyright (C) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
If you have Invariant Sections, Front-Cover Texts and Back-Cover
Texts, replace the "with...Texts." line with this:
with the Invariant Sections being LIST THEIR TITLES, with
the Front-Cover Texts being LIST, and with the Back-Cover Texts
being LIST.
If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.
If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License, to
permit their use in free software.

File: libgomp.info, Node: Funding, Next: Library Index, Prev: GNU Free Documentation License, Up: Top
Funding Free Software
*********************
If you want to have more free software a few years from now, it makes
sense for you to help encourage people to contribute funds for its
development. The most effective approach known is to encourage
commercial redistributors to donate.
Users of free software systems can boost the pace of development by
encouraging for-a-fee distributors to donate part of their selling price
to free software developers--the Free Software Foundation, and others.
The way to convince distributors to do this is to demand it and
expect it from them. So when you compare distributors, judge them
partly by how much they give to free software development. Show
distributors they must compete to be the one who gives the most.
To make this approach work, you must insist on numbers that you can
compare, such as, "We will donate ten dollars to the Frobnitz project
for each disk sold." Don't be satisfied with a vague promise, such as
"A portion of the profits are donated," since it doesn't give a basis
for comparison.
Even a precise fraction "of the profits from this disk" is not very
meaningful, since creative accounting and unrelated business decisions
can greatly alter what fraction of the sales price counts as profit.
If the price you pay is $50, ten percent of the profit is probably less
than a dollar; it might be a few cents, or nothing at all.
Some redistributors do development work themselves. This is useful
too; but to keep everyone honest, you need to inquire how much they do,
and what kind. Some kinds of development make much more long-term
difference than others. For example, maintaining a separate version of
a program contributes very little; maintaining the standard version of a
program for the whole community contributes much. Easy new ports
contribute little, since someone else would surely do them; difficult
ports such as adding a new CPU to the GNU Compiler Collection
contribute more; major new features or packages contribute the most.
By establishing the idea that supporting further development is "the
proper thing to do" when distributing free software for a fee, we can
assure a steady flow of resources into making more free software.
Copyright (C) 1994 Free Software Foundation, Inc.
Verbatim copying and redistribution of this section is permitted
without royalty; alteration is not permitted.

File: libgomp.info, Node: Library Index, Prev: Funding, Up: Top
Library Index
*************
�[index�]
* Menu:
* Environment Variable <1>: GOMP_STACKSIZE. (line 6)
* Environment Variable <2>: GOMP_CPU_AFFINITY. (line 6)
* Environment Variable <3>: OMP_PROC_BIND. (line 6)
* Environment Variable <4>: OMP_WAIT_POLICY. (line 6)
* Environment Variable <5>: OMP_THREAD_LIMIT. (line 6)
* Environment Variable <6>: OMP_STACKSIZE. (line 6)
* Environment Variable <7>: OMP_SCHEDULE. (line 6)
* Environment Variable <8>: OMP_NUM_THREADS. (line 6)
* Environment Variable <9>: OMP_NESTED. (line 6)
* Environment Variable <10>: OMP_MAX_ACTIVE_LEVELS. (line 6)
* Environment Variable: OMP_DYNAMIC. (line 6)
* FDL, GNU Free Documentation License: GNU Free Documentation License.
(line 6)
* Implementation specific setting <1>: GOMP_STACKSIZE. (line 6)
* Implementation specific setting <2>: OMP_SCHEDULE. (line 6)
* Implementation specific setting <3>: OMP_NUM_THREADS. (line 6)
* Implementation specific setting: OMP_NESTED. (line 6)
* Introduction: Top. (line 6)

Tag Table:
Node: Top2116
Node: Enabling OpenMP3310
Node: Runtime Library Routines4095
Node: omp_get_active_level6543
Node: omp_get_ancestor_thread_num7247
Node: omp_get_dynamic8174
Node: omp_get_level9052
Node: omp_get_max_active_levels9676
Node: omp_get_max_threads10379
Node: omp_get_nested11135
Node: omp_get_num_procs12047
Node: omp_get_num_threads12565
Node: omp_get_schedule13647
Node: omp_get_team_size14568
Node: omp_get_thread_limit15530
Node: omp_get_thread_num16153
Node: omp_in_parallel17021
Node: omp_in_final17668
Node: omp_set_dynamic18339
Node: omp_set_max_active_levels19176
Node: omp_set_nested19956
Node: omp_set_num_threads20835
Node: omp_set_schedule21671
Node: omp_init_lock22743
Node: omp_set_lock23394
Node: omp_test_lock24245
Node: omp_unset_lock25216
Node: omp_destroy_lock26142
Node: omp_init_nest_lock26816
Node: omp_set_nest_lock27549
Node: omp_test_nest_lock28460
Node: omp_unset_nest_lock29489
Node: omp_destroy_nest_lock30499
Node: omp_get_wtick31247
Node: omp_get_wtime31838
Node: Environment Variables32612
Node: OMP_DYNAMIC33740
Node: OMP_MAX_ACTIVE_LEVELS34308
Node: OMP_NESTED34947
Node: OMP_NUM_THREADS35551
Node: OMP_SCHEDULE36239
Node: OMP_STACKSIZE36933
Node: OMP_THREAD_LIMIT37759
Node: OMP_WAIT_POLICY38354
Node: OMP_PROC_BIND38915
Node: GOMP_CPU_AFFINITY39473
Node: GOMP_STACKSIZE41014
Node: The libgomp ABI41824
Node: Implementing MASTER construct42623
Node: Implementing CRITICAL construct43037
Node: Implementing ATOMIC construct43776
Node: Implementing FLUSH construct44257
Node: Implementing BARRIER construct44528
Node: Implementing THREADPRIVATE construct44797
Node: Implementing PRIVATE clause45449
Node: Implementing FIRSTPRIVATE LASTPRIVATE COPYIN and COPYPRIVATE clauses46030
Node: Implementing REDUCTION clause47354
Node: Implementing PARALLEL construct47911
Node: Implementing FOR construct49168
Node: Implementing ORDERED construct51166
Node: Implementing SECTIONS construct51472
Node: Implementing SINGLE construct52238
Node: Reporting Bugs52900
Node: Copying53210
Node: GNU Free Documentation License90775
Node: Funding115917
Node: Library Index118442

End Tag Table