pthread_mutexattr_getpshared3p
Get and set the process-shared attribute
Usage
#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);
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.
Overview
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.