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'\" et
.TH semaphore.h "0P" 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
semaphore.h
\(em semaphores
.SH SYNOPSIS
.LP
.nf
#include <semaphore.h>
.fi
.SH DESCRIPTION
The
.IR <semaphore.h>
header shall define the
.BR 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.
.P
The
.IR <semaphore.h>
header shall define the symbolic constant SEM_FAILED which shall
have type
.BR "sem_t *" .
.P
The following shall be declared as functions and may also be defined
as macros. Function prototypes shall be provided.
.sp
.RS 4
.nf
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 *);
.fi
.P
.RE
.P
Inclusion of the
.IR <semaphore.h>
header may make visible symbols defined in the
.IR <fcntl.h>
and
.IR <time.h>
headers.
.LP
.IR "The following sections are informative."
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fB<fcntl.h>\fP",
.IR "\fB<sys_types.h>\fP",
.IR "\fB<time.h>\fP"
.P
The System Interfaces volume of POSIX.1\(hy2017,
.IR "\fIsem_close\fR\^(\|)",
.IR "\fIsem_destroy\fR\^(\|)",
.IR "\fIsem_getvalue\fR\^(\|)",
.IR "\fIsem_init\fR\^(\|)",
.IR "\fIsem_open\fR\^(\|)",
.IR "\fIsem_post\fR\^(\|)",
.IR "\fIsem_timedwait\fR\^(\|)",
.IR "\fIsem_trywait\fR\^(\|)",
.IR "\fIsem_unlink\fR\^(\|)"
.\"
.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 .
|
