PTHREAD_GET

NAME    [Toc]    [Back]

     pthread_getconcurrency, pthread_setconcurrency - get or  set
level of concurrency

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]

     pthread_setconcurrency() 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.

OpenBSD     3.6                          April      11,      2003