man7.org > Linux > man-pages

Linux/UNIX system programming training

semaphore.h(0p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT 

semaphore.h(0P)         POSIX Programmer's Manual        semaphore.h(0P)

PROLOG         top

       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.

NAME         top

       semaphore.h — semaphores

SYNOPSIS         top

       #include <semaphore.h>

DESCRIPTION         top

       The <semaphore.h> header shall define the sem_t type, used in
       performing semaphore operations. The semaphore may be implemented
       using a file descriptor, in which case applications are able to
       open up at least a total of {OPEN_MAX} files and semaphores.

       The <semaphore.h> header shall define the symbolic constant
       SEM_FAILED which shall have type sem_t *.

       The following shall be declared as functions and may also be
       defined as macros. Function prototypes shall be provided.

           int    sem_close(sem_t *);
           int    sem_destroy(sem_t *);
           int    sem_getvalue(sem_t *restrict, int *restrict);
           int    sem_init(sem_t *, int, unsigned);
           sem_t *sem_open(const char *, int, ...);
           int    sem_post(sem_t *);
           int    sem_timedwait(sem_t *restrict, const struct timespec *restrict);
           int    sem_trywait(sem_t *);
           int    sem_unlink(const char *);
           int    sem_wait(sem_t *);

       Inclusion of the <semaphore.h> header may make visible symbols
       defined in the <fcntl.h> and <time.h> headers.

       The following sections are informative.

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       fcntl.h(0p), sys_types.h(0p), time.h(0p)

       The System Interfaces volume of POSIX.1‐2017, sem_close(3p),
       sem_destroy(3p), sem_getvalue(3p), sem_init(3p), sem_open(3p),
       sem_post(3p), sem_timedwait(3p), sem_trywait(3p), sem_unlink(3p)

COPYRIGHT         top

       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:https://www.opengroup.org/unix/online.html .

       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 .

IEEE/The Open Group               2017                   semaphore.h(0P)

Pages that refer to this page: spawn.h(0p),  sem_close(3p),  sem_destroy(3p),  sem_getvalue(3p),  sem_init(3p),  sem_open(3p),  sem_post(3p),  sem_timedwait(3p),  sem_trywait(3p),  sem_unlink(3p)

HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface.

For details of in-depth Linux/UNIX system programming training courses that I teach, look here.

Hosting by jambit GmbH.

Cover of TLPI