👤
Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:
Select Section of Man Page:
Select Man Page Repository:

Linux 2.6 - man page for pthread_getconcurrency (linux section 3)

PTHREAD_SETCONCURRENCY(3)	    Linux Programmer's Manual		PTHREAD_SETCONCURRENCY(3)

NAME
       pthread_setconcurrency, pthread_getconcurrency - set/get the concurrency level

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  num-
       ber.

       pthread_getconcurrency()  always succeeds, returning the concurrency level set by a previ-
       ous 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.1-2001 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.

CONFORMING TO
       POSIX.1-2001.

NOTES
       The default concurrency level is 0.

       Concurrency levels are meaningful only for M:N threading  implementations,  where  at  any
       moment  a subset of a process's set of user-level threads may be bound to a smaller number
       of kernel-scheduling entities.  Setting the concurrency level allows  the  application  to
       give  the system a hint as to the number of kernel-scheduling entities that should be pro-
       vided for efficient execution of the application.

       Both LinuxThreads and NPTL are 1:1 threading implementations, so setting  the  concurrency
       level  has no meaning.  In other words, on Linux these functions merely exist for compati-
       bility with other systems, and they have no effect on the execution of a program.

SEE ALSO
       pthread_attr_setscope(3), pthreads(7)

COLOPHON
       This page is part of release 3.55 of the Linux man-pages project.  A  description  of  the
       project,     and    information	  about    reporting	bugs,	 can	be    found    at
       http://www.kernel.org/doc/man-pages/.

Linux					    2009-04-10			PTHREAD_SETCONCURRENCY(3)


All times are GMT -4. The time now is 07:07 AM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
×
UNIX.COM Login
Username:
Password:  
Show Password





Not a Forum Member?
Forgot Password?