pthread_getconcurrency

SYNOPSIS
       #include <pthread.h>

       int pthread_setconcurrency(int new_level);
       int pthread_getconcurrency(void);

       Compile and link with -pthread.

DESCRIPTION
       The pthread_setconcurrency() function informs the implementation of the
       application's  desired  concurrency level, specified in new_level.  The
       implementation takes this only as a hint: POSIX.1 does not specify  the
       level  of  concurrency  that  should be provided as a result of calling
       pthread_setconcurrency().

       Specifying new_level as 0 instructs the implementation  to  manage  the
       concurrency level as it deems appropriate.

       pthread_getconcurrency()  returns  the current value of the concurrency
       level for this process.

RETURN VALUE
       On success, pthread_setconcurrency() returns 0; on error, it returns  a
       nonzero error number.

       pthread_getconcurrency()  always  succeeds,  returning  the concurrency
       level set by a previous call  to  pthread_setconcurrency(),  or  0,  if
       pthread_setconcurrency() has not previously been called.

ERRORS
       pthread_setconcurrency() can fail with the following error:

       EINVAL new_level is negative.

       POSIX.1  also  documents  an  EAGAIN  error  ("the  value  specified by
       new_level would cause a system resource to be exceeded").

VERSIONS
       These functions are available in glibc since version 2.1.

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       +--------------------------+---------------+---------+
       |Interface                 | Attribute     | Value   |
       +--------------------------+---------------+---------+
       |pthread_setconcurrency(), | Thread safety | MT-Safe |
       |pthread_getconcurrency()  |               |         |
       +--------------------------+---------------+---------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

NOTES
       they have no effect on the execution of a program.

SEE ALSO
       pthread_attr_setscope(3), pthreads(7)

COLOPHON
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Linux                             2015-08-08         PTHREAD_SETCONCURRENCY(3)
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