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diff --git a/man-pages-posix-2017/man3p/pthread_getconcurrency.3p b/man-pages-posix-2017/man3p/pthread_getconcurrency.3p new file mode 100644 index 0000000..67c640a --- /dev/null +++ b/man-pages-posix-2017/man3p/pthread_getconcurrency.3p @@ -0,0 +1,142 @@ +'\" et +.TH PTHREAD_GETCONCURRENCY "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.\" +.SH NAME +pthread_getconcurrency, +pthread_setconcurrency +\(em get and set the level of concurrency +.SH SYNOPSIS +.LP +.nf +#include <pthread.h> +.P +int pthread_getconcurrency(void); +int pthread_setconcurrency(int \fInew_level\fP); +.fi +.SH DESCRIPTION +Unbound threads in a process may or may not be required to be +simultaneously active. By default, the threads implementation ensures +that a sufficient number of threads are active so that the process can +continue to make progress. While this conserves system resources, it +may not produce the most effective level of concurrency. +.P +The +\fIpthread_setconcurrency\fR() +function allows an application to inform the threads implementation of +its desired concurrency level, +.IR new_level . +The actual level of concurrency provided by the implementation as a +result of this function call is unspecified. +.P +If +.IR new_level +is zero, it causes the implementation to maintain the concurrency level +at its discretion as if +\fIpthread_setconcurrency\fR() +had never been called. +.P +The +\fIpthread_getconcurrency\fR() +function shall return the value set by a previous call to the +\fIpthread_setconcurrency\fR() +function. If the +\fIpthread_setconcurrency\fR() +function was not previously called, this function shall return zero to +indicate that the implementation is maintaining the concurrency level. +.P +A call to +\fIpthread_setconcurrency\fR() +shall inform the implementation of its desired concurrency level. +The implementation shall use this as a hint, not a requirement. +.P +If an implementation does not support multiplexing of user threads on +top of several kernel-scheduled entities, the +\fIpthread_setconcurrency\fR() +and +\fIpthread_getconcurrency\fR() +functions are provided for source code compatibility but they shall +have no effect when called. To maintain the function semantics, the +.IR new_level +parameter is saved when +\fIpthread_setconcurrency\fR() +is called so that a subsequent call to +\fIpthread_getconcurrency\fR() +shall return the same value. +.SH "RETURN VALUE" +If successful, the +\fIpthread_setconcurrency\fR() +function shall return zero; otherwise, an error number shall be +returned to indicate the error. +.P +The +\fIpthread_getconcurrency\fR() +function shall always return the concurrency level set by a previous +call to +\fIpthread_setconcurrency\fR(). +If the +\fIpthread_setconcurrency\fR() +function has never been called, +\fIpthread_getconcurrency\fR() +shall return zero. +.SH ERRORS +The +\fIpthread_setconcurrency\fR() +function shall fail if: +.TP +.BR EINVAL +The value specified by +.IR new_level +is negative. +.TP +.BR EAGAIN +The value specified by +.IR new_level +would cause a system resource to be exceeded. +.P +The +\fIpthread_setconcurrency\fR() +function shall not return an error code of +.BR [EINTR] . +.LP +.IR "The following sections are informative." +.SH EXAMPLES +None. +.SH "APPLICATION USAGE" +Application developers should note that an implementation can always +ignore any calls to +\fIpthread_setconcurrency\fR() +and return a constant for +\fIpthread_getconcurrency\fR(). +For this reason, it is not recommended that portable applications +use this function. +.SH RATIONALE +None. +.SH "FUTURE DIRECTIONS" +These functions may be removed in a future version. +.SH "SEE ALSO" +The Base Definitions volume of POSIX.1\(hy2017, +.IR "\fB<pthread.h>\fP" +.\" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1-2017, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, 2018 Edition, +Copyright (C) 2018 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +In the event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . +.PP +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |