1<semaphore.h>(0P)          POSIX Programmer's Manual         <semaphore.h>(0P)
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NAME

6       semaphore.h - semaphores (REALTIME)
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SYNOPSIS

9       #include <semaphore.h>
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DESCRIPTION

12       The  <semaphore.h> header shall define the sem_t type, used in perform‐
13       ing semaphore operations. The semaphore may be implemented using a file
14       descriptor,  in  which case applications are able to open up at least a
15       total of {OPEN_MAX} files and semaphores. The symbol  SEM_FAILED  shall
16       be defined (see sem_open()).
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18       The following shall be declared as functions and may also be defined as
19       macros. Function prototypes shall be provided.
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22              int    sem_close(sem_t *);
23              int    sem_destroy(sem_t *);
24              int    sem_getvalue(sem_t *restrict, int *restrict);
25              int    sem_init(sem_t *, int, unsigned);
26              sem_t *sem_open(const char *, int, ...);
27              int    sem_post(sem_t *);
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29              int    sem_timedwait(sem_t *restrict, const struct timespec *restrict);
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31              int    sem_trywait(sem_t *);
32              int    sem_unlink(const char *);
33              int    sem_wait(sem_t *);
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35       Inclusion of the <semaphore.h> header may make visible symbols  defined
36       in the headers <fcntl.h> and <sys/types.h>.
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38       The following sections are informative.
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APPLICATION USAGE

41       None.
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RATIONALE

44       None.
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FUTURE DIRECTIONS

47       None.
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SEE ALSO

50       <fcntl.h>,    <sys/types.h>,    the   System   Interfaces   volume   of
51       IEEE Std 1003.1-2001,   sem_destroy(),   sem_getvalue(),    sem_init(),
52       sem_open(),  sem_post(),  sem_timedwait(), sem_trywait(), sem_unlink(),
53       sem_wait()
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56       Portions of this text are reprinted and reproduced in  electronic  form
57       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
58       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
59       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
60       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
61       event of any discrepancy between this version and the original IEEE and
62       The Open Group Standard, the original IEEE and The Open Group  Standard
63       is  the  referee document. The original Standard can be obtained online
64       at http://www.opengroup.org/unix/online.html .
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68IEEE/The Open Group                  2003                    <semaphore.h>(0P)
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