# pthread_mutexattr_getpshared

## 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.
    


## NAME



           pthread_mutexattr_getpshared, pthread_mutexattr_setpshared — get
           and set the process-shared attribute
    


## SYNOPSIS



           #include <pthread.h>
    
           int pthread_mutexattr_getpshared(const pthread_mutexattr_t
               *restrict _attr_ , int *restrict _pshared_);
           int pthread_mutexattr_setpshared(pthread_mutexattr_t *_attr_ ,
               int _pshared_);
    


## DESCRIPTION



           The _pthread_mutexattr_getpshared_() function shall obtain the value
           of the _process-shared_ attribute from the attributes object
           referenced by _attr_.
    
           The _pthread_mutexattr_setpshared_() function shall set the _process-_
           _shared_ attribute in an initialized attributes object referenced by
           _attr_.
    
           The _process-shared_ attribute is set to PTHREAD_PROCESS_SHARED to
           permit a mutex to be operated upon by any thread that has access
           to the memory where the mutex is allocated, even if the mutex is
           allocated in memory that is shared by multiple processes. See
           _Section 2.9.9_ , _Synchronization Object Copies and Alternative_
           _Mappings_ for further requirements. The default value of the
           attribute shall be PTHREAD_PROCESS_PRIVATE.
    
           The behavior is undefined if the value specified by the _attr_
           argument to _pthread_mutexattr_getpshared_() or
           _pthread_mutexattr_setpshared_() does not refer to an initialized
           mutex attributes object.
    


## RETURN VALUE



           Upon successful completion, _pthread_mutexattr_setpshared_() shall
           return zero; otherwise, an error number shall be returned to
           indicate the error.
    
           Upon successful completion, _pthread_mutexattr_getpshared_() shall
           return zero and store the value of the _process-shared_ attribute of
           _attr_ into the object referenced by the _pshared_ parameter.
           Otherwise, an error number shall be returned to indicate the
           error.
    


## ERRORS



           The _pthread_mutexattr_setpshared_() function may fail if:
    
           **EINVAL** The new value specified for the attribute is outside the
                  range of legal values for that attribute.
    
           These functions shall not return an error code of **[EINTR]**.
    
           _The following sections are informative._
    


## EXAMPLES



           None.
    


## APPLICATION USAGE



           None.
    


## RATIONALE



           If an implementation detects that the value specified by the _attr_
           argument to _pthread_mutexattr_getpshared_() or
           _pthread_mutexattr_setpshared_() does not refer to an initialized
           mutex attributes object, it is recommended that the function
           should fail and report an **[EINVAL]** error.
    


## FUTURE DIRECTIONS



           None.
    


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