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Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions 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. This notice shall appear on any product containing this material. .TH pthread_mutex_init 3C "11 Jan 2012" "SunOS 5.11" "Standard C Library Functions" .SH NAME pthread_mutex_init, pthread_mutex_destroy \- initialize or destroy a mutex .SH SYNOPSIS .LP .nf cc -mt [ \fIflag\fR... ] \fIfile\fR... [ \fIlibrary\fR... ] #include \fBint\fR \fBpthread_mutex_init\fR(\fBpthread_mutex_t *restrict\fR \fImutex\fR, \fBconst pthread_mutexattr_t *restrict\fR \fIattr\fR); .fi .LP .nf \fBint\fR \fBpthread_mutex_destroy\fR(\fBpthread_mutex_t *\fR\fImutex\fR); .fi .LP .nf \fBpthread_mutex_t\fR \fImutex\fR= \fBPTHREAD_MUTEX_INITIALIZER\fR; .fi .SH DESCRIPTION .sp .LP The \fBpthread_mutex_init()\fR function initializes the mutex referenced by \fImutex\fR with attributes specified by \fIattr\fR. If \fIattr\fR is \fINULL\fR, the default mutex attributes are used; the effect is the same as passing the address of a default mutex attributes object. Upon successful initialization, the state of the mutex becomes initialized and unlocked. .sp .LP Except for robust mutexes, attempting to initialize an already initialized mutex results in undefined behavior. .sp .LP The \fBpthread_mutex_destroy()\fR function destroys the mutex object referenced by \fImutex\fR; the mutex object becomes, in effect, uninitialized. A destroyed mutex object can be re-initialized using \fBpthread_mutex_init()\fR; the results of otherwise referencing the object after it has been destroyed are undefined. .sp .LP It is safe to destroy an initialized mutex that is unlocked. Attempting to destroy a locked mutex results in undefined behavior. .sp .LP In cases where default mutex attributes are appropriate, the macro \fBPTHREAD_MUTEX_INITIALIZER\fR can be used to initialize mutexes that are statically allocated. The effect is equivalent to dynamic initialization by a call to \fBpthread_mutex_init()\fR with parameter \fIattr\fR specified as \fINULL\fR, except that no error checks are performed. .SH RETURN VALUES .sp .LP If successful, the \fBpthread_mutex_init()\fR and \fBpthread_mutex_destroy()\fR functions return \fB0\fR. Otherwise, an error number is returned to indicate the error. .SH ERRORS .sp .LP The \fBpthread_mutex_init()\fR function will fail if: .sp .ne 2 .mk .na \fB\fBEAGAIN\fR\fR .ad .RS 10n .rt The system lacked the necessary resources (other than memory) to initialize another mutex. .RE .sp .ne 2 .mk .na \fB\fBEBUSY\fR\fR .ad .RS 10n .rt An attempt was detected to re-initialize a robust mutex previously initialized but not yet destroyed. See \fBpthread_mutexattr_setrobust\fR(3C). .RE .sp .ne 2 .mk .na \fB\fBEINVAL\fR\fR .ad .RS 10n .rt An attempt was detected to re-initialize a robust mutex previously initialized with a different set of attributes. See \fBpthread_mutexattr_setrobust\fR(3C). .RE .sp .ne 2 .mk .na \fB\fBENOMEM\fR\fR .ad .RS 10n .rt Insufficient memory exists to initialize the mutex. .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 .sp .LP The \fBpthread_mutex_init()\fR function may fail if: .sp .ne 2 .mk .na \fB\fBEBUSY\fR\fR .ad .RS 10n .rt An attempt was detected to re-initialize the object referenced by \fImutex\fR, a mutex previously initialized but not yet destroyed. .RE .sp .ne 2 .mk .na \fB\fBEINVAL\fR\fR .ad .RS 10n .rt The value specified by \fIattr\fR or \fImutex\fR is invalid. .RE .sp .LP The \fBpthread_mutex_destroy()\fR function may fail if: .sp .ne 2 .mk .na \fB\fBEBUSY\fR\fR .ad .RS 10n .rt An attempt was detected to destroy the object referenced by \fImutex\fR while it is locked or referenced (for example, while being used in a \fBpthread_cond_wait\fR(3C) or \fBpthread_cond_timedwait\fR(3C)) by another thread. .RE .sp .ne 2 .mk .na \fB\fBEINVAL\fR\fR .ad .RS 10n .rt The value specified by \fImutex\fR is invalid. .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_cond_wait\fR(3C), \fBpthread_mutex_lock\fR(3C), \fBpthread_mutexattr_setprioceiling\fR(3C), \fBpthread_mutexattr_setprotocol\fR(3C), \fBpthread_mutexattr_setpshared\fR(3C), \fBpthread_mutexattr_setrobust\fR(3C), \fBpthread_mutexattr_settype\fR(3C), \fBattributes\fR(5), \fBmutex\fR(5), \fBstandards\fR(5)