1semaphore.h(0P)            POSIX Programmer's Manual           semaphore.h(0P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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NAME

13       semaphore.h — semaphores
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SYNOPSIS

16       #include <semaphore.h>
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DESCRIPTION

19       The <semaphore.h> header shall define the sem_t type, used in  perform‐
20       ing semaphore operations. The semaphore may be implemented using a file
21       descriptor, in which case applications are able to open up at  least  a
22       total of {OPEN_MAX} files and semaphores.
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24       The  <semaphore.h> header shall define the symbolic constant SEM_FAILED
25       which shall have type sem_t *.
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27       The following shall be declared as functions and may also be defined as
28       macros. Function prototypes shall be provided.
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30           int    sem_close(sem_t *);
31           int    sem_destroy(sem_t *);
32           int    sem_getvalue(sem_t *restrict, int *restrict);
33           int    sem_init(sem_t *, int, unsigned);
34           sem_t *sem_open(const char *, int, ...);
35           int    sem_post(sem_t *);
36           int    sem_timedwait(sem_t *restrict, const struct timespec *restrict);
37           int    sem_trywait(sem_t *);
38           int    sem_unlink(const char *);
39           int    sem_wait(sem_t *);
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41       Inclusion  of the <semaphore.h> header may make visible symbols defined
42       in the <fcntl.h> and <time.h> headers.
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44       The following sections are informative.
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APPLICATION USAGE

47       None.
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RATIONALE

50       None.
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FUTURE DIRECTIONS

53       None.
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SEE ALSO

56       <fcntl.h>, <sys_types.h>, <time.h>
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58       The   System   Interfaces   volume   of   POSIX.1‐2008,    sem_close(),
59       sem_destroy(),   sem_getvalue(),  sem_init(),  sem_open(),  sem_post(),
60       sem_timedwait(), sem_trywait(), sem_unlink()
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63       Portions of this text are reprinted and reproduced in  electronic  form
64       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
65       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
66       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
67       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
68       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) In the
69       event of any discrepancy between this version and the original IEEE and
70       The  Open Group Standard, the original IEEE and The Open Group Standard
71       is the referee document. The original Standard can be  obtained  online
72       at http://www.unix.org/online.html .
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74       Any  typographical  or  formatting  errors that appear in this page are
75       most likely to have been introduced during the conversion of the source
76       files  to  man page format. To report such errors, see https://www.ker‐
77       nel.org/doc/man-pages/reporting_bugs.html .
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81IEEE/The Open Group                  2013                      semaphore.h(0P)
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