PTHREAD_GETCONCURRE... FreeBSD Library Functions Manual PTHREAD_GETCONCURRE...

NAME    [Toc]    [Back]

     pthread_getconcurrency, pthread_setconcurrency -- get or set level of
     concurrency

LIBRARY    [Toc]    [Back]

     Reentrant C Library (libc_r, -lc_r)

SYNOPSIS    [Toc]    [Back]

     #include <pthread.h>

     int
     pthread_getconcurrency(void);

     int
     pthread_setconcurrency(int new_level);

DESCRIPTION    [Toc]    [Back]

     The pthread_getconcurrency() function allows an application to inform the
     threads implementation of its desired concurrency level, new_level.  The
     actual level of concurrency provided by the implementation as a result of
     this function call is unspecified.  If new_level is zero, it causes the
     implementation to maintain the concurrency level at its discretion as if
     pthread_setconcurrency() was never called.  The pthread_getconcurrency()
     function returns the value set by a previous call to the
     pthread_setconcurrency() function.  If the pthread_setconcurrency() function
 was not previously called, this function returns zero to indicate
     that the implementation is maintaining the concurrency level.  When an
     application calls pthread_setconcurrency(), it is informing the implementation
 of its desired concurrency level.  The implementation uses this as
     a hint, not a requirement.

RETURN VALUES    [Toc]    [Back]

     If successful, the pthread_setconcurrency() function returns zero.  Otherwise,
 an error number is returned to indicate the error.  The
     pthread_getconcurrency() function always returns the concurrency level
     set by a previous call to pthread_setconcurrency().  If the
     pthread_setconcurrency() function has never been called,
     pthread_getconcurrency() returns zero.

ERRORS    [Toc]    [Back]

     The pthread_setconcurrency() function will fail if:

     [EINVAL]		The value specified by new_level is negative.

     [EAGAIN]		The value specified by new_level would cause a system
			resource to be exceeded.

APPLICATION USAGE    [Toc]    [Back]

     Use of these functions changes the state of the underlying concurrency
     upon which the application depends.  Library developers are advised to
     not use the pthread_getconcurrency() and pthread_setconcurrency() functions
 since their use may conflict with an application's use of these
     functions.

STANDARDS    [Toc]    [Back]

     The pthread_getconcurrency() and pthread_setconcurrency() functions conform
 to Version 2 of the Single UNIX Specification (``SUSv2'').


FreeBSD 5.2.1			April 11, 2003			 FreeBSD 5.2.1