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.TH sem.h 3HEAD "10 Sep 2004" "SunOS 5.11" "Headers"
.SH NAME
sem.h, sem \- semaphore facility
.SH SYNOPSIS
.LP
.nf
#include <\fBsys/sem.h\fR>
.fi
.SH DESCRIPTION
.sp
.LP
The <\fBsys/sem.h\fR> header defines the following constants and structures.
.sp
.LP
Semaphore operation flags:
.sp
.ne 2
.mk
.na
\fB\fBSEM_UNDO\fR\fR
.ad
.RS 12n
.rt
Set up adjust on exit entry.
.RE
.sp
.LP
Command definitions for the \fBsemctl()\fR function are provided as listed below. See \fBsemctl\fR(2).
.sp
.ne 2
.mk
.na
\fB\fBGETNCNT\fR\fR
.ad
.RS 11n
.rt
Get \fBsemncnt\fR.
.RE
.sp
.ne 2
.mk
.na
\fB\fBGETPID\fR\fR
.ad
.RS 11n
.rt
Get \fBsempid\fR.
.RE
.sp
.ne 2
.mk
.na
\fB\fBGETVAL\fR\fR
.ad
.RS 11n
.rt
Get \fBsemval\fR.
.RE
.sp
.ne 2
.mk
.na
\fB\fBGETALL\fR\fR
.ad
.RS 11n
.rt
Get all cases of \fBsemval\fR.
.RE
.sp
.ne 2
.mk
.na
\fB\fBGETZCNT\fR\fR
.ad
.RS 11n
.rt
Get \fBsemzcnt\fR.
.RE
.sp
.ne 2
.mk
.na
\fB\fBSETVAL\fR\fR
.ad
.RS 11n
.rt
Set \fBsemval\fR.
.RE
.sp
.ne 2
.mk
.na
\fB\fBSETALL\fR\fR
.ad
.RS 11n
.rt
Set all cases of \fBsemval\fR.
.RE
.sp
.LP
The \fBsemid_ds\fR structure contains the following members:
.sp
.in +2
.nf
struct ipc_perm sem_perm /* operation permission structure */
unsigned short sem_nsems /* number of semaphores in set */
time_t sem_otime /* last \fBsemop()\fR time */
time_t sem_ctime /* last time changed by \fBsemctl()\fR */
.fi
.in -2
.sp
.LP
The \fBpid_t\fR, \fBtime_t\fR, \fBkey_t\fR, and \fBsize_t\fR types are defined as described in <\fBsys/types.h\fR>. See \fBtypes.h\fR(3HEAD).
.sp
.LP
A semaphore is represented by an anonymous structure containing the following members:
.sp
.in +2
.nf
unsigned short semval /* semaphore value */
pid_t sempid /* process ID of last operation */
unsigned short semncnt /* number of processes waiting for \fBsemval\fR
to become greater than current value */
unsigned short semzcnt /* number of processes waiting for \fBsemval\fR
to become 0 */
.fi
.in -2
.sp
.LP
The \fBsembuf\fR structure contains the following members:
.sp
.in +2
.nf
unsigned short sem_num /* semaphore number */
short sem_op /* semaphore operation */
short sem_flg /* operation flags */
.fi
.in -2
.sp
.LP
All of the symbols from <\fBsys/ipc.h\fR> are defined when this header is included. See \fBipc.h\fR(3HEAD).
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp
.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i)
lw(2.75i) |lw(2.75i)
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityCommitted
_
StandardSee \fBstandards\fR(5).
.TE
.SH SEE ALSO
.sp
.LP
\fBsemctl\fR(2), \fBsemget\fR(2), \fBsemop\fR(2), \fBipc.h\fR(3HEAD), \fBtypes.h\fR(3HEAD), \fBattributes\fR(5), \fBstandards\fR(5)