NAME
semaphore.h - semaphores (REALTIME)
SYNOPSIS
#include <semaphore.h>
DESCRIPTION
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 symbol SEM_FAILED
shall be defined (see sem_open()).
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 headers <fcntl.h> and <sys/types.h>.
The following sections are informative.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
<fcntl.h> , <sys/types.h> , the System Interfaces volume of
IEEE Std 1003.1-2001, sem_destroy(), sem_getvalue(), sem_init(),
sem_open(), sem_post(), sem_timedwait(), sem_trywait(), sem_unlink(),
sem_wait()
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 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 .