'\" te
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.TH pthread_mutex_getprioceiling 3C "11 Jan 2012" "SunOS 5.11" "Standard C Library Functions"
.SH NAME
pthread_mutex_getprioceiling, pthread_mutex_setprioceiling \- change priority ceiling of a mutex
.SH SYNOPSIS
.LP
.nf
cc -mt [ \fIflag\fR... ] \fIfile\fR... [ \fIlibrary\fR... ]
#include <pthread.h>

\fBint\fR \fBpthread_mutex_getprioceiling\fR(\fBconst pthread_mutex_t *restrict\fR \fImutex\fR,
     \fBint *restrict\fR \fIprioceiling\fR);
.fi

.LP
.nf
\fBint\fR \fBpthread_mutex_setprioceiling\fR(\fBpthread_mutex_t *restrict\fR \fImutex\fR,
     \fBint\fR \fIprioceiling\fR, \fBint *restrict\fR \fIold_ceiling\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBpthread_mutex_getprioceiling()\fR function returns the current priority ceiling of the mutex.
.sp
.LP
The \fBpthread_mutex_setprioceiling()\fR function either locks the mutex if it is unlocked, or blocks until it can successfully lock the mutex, then it changes the mutex's priority ceiling and releases the mutex. When the change is successful, the previous value of the priority ceiling is returned in \fIold_ceiling\fR. The process of locking the mutex need not adhere to the priority protect protocol.
.sp
.LP
If the \fBpthread_mutex_setprioceiling()\fR function fails, the mutex priority ceiling is not changed.
.sp
.LP
The ceiling value should be drawn from the range of priorities for the \fBSCHED_FIFO\fR policy. When a thread acquires such a mutex, the policy of the thread at mutex acquisition should match that from which the ceiling value was derived (\fBSCHED_FIFO\fR, in this case).    If a thread changes its scheduling policy while holding a ceiling mutex, the  behavior of \fBpthread_mutex_lock()\fR and \fBpthread_mutex_unlock()\fR on this mutex is undefined. See \fBpthread_mutex_lock\fR(3C).
.sp
.LP
The ceiling value should not be treated as a persistent value resident in a \fBpthread_mutex_t\fR that is valid across upgrades of Solaris. The semantics of the actual ceiling value are determined by the existing priority range for the \fBSCHED_FIFO\fR policy, as returned  by the \fBsched_get_priority_min()\fR and \fBsched_get_priority_max()\fR functions (see \fBsched_get_priority_min\fR(3C)) when called on the version of Solaris on which the ceiling value is being utilized.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, the \fBpthread_mutex_getprioceiling()\fR and \fBpthread_mutex_setprioceiling()\fR functions return  \fB0\fR. Otherwise, an error number is returned to indicate the error.
.SH ERRORS
.sp
.LP
The  \fBpthread_mutex_getprioceiling()\fR and \fBpthread_mutex_setprioceiling()\fR functions may fail if:
.sp
.ne 2
.mk
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
.rt  
The value specified by \fImutex\fR does not refer to a currently existing mutex.
.RE

.sp
.LP
The \fBpthread_mutex_setprioceiling()\fR function will fail if:
.sp
.ne 2
.mk
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
.rt  
The mutex was not initialized with its \fIprotocol\fR attribute having the value of \fBPTHREAD_PRIO_PROTECT\fR.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
.rt  
The priority requested by \fIprioceiling\fR is out of range.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEPERM\fR\fR
.ad
.RS 10n
.rt  
The caller does not have the privilege to perform the operation.
.RE

.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
_
MT-LevelMT-Safe
_
StandardSee \fBstandards\fR(5).
.TE

.SH SEE ALSO
.sp
.LP
\fBpthread_mutex_init\fR(3C), \fBpthread_mutex_lock\fR(3C), \fBsched_get_priority_min\fR(3C), \fBattributes\fR(5), \fBstandards\fR(5)