pthread_mutexattr_getpshared, pthread_mutexattr_setpshared - get/set
process-shared mutex attribute
#include <pthread.h>
int pthread_mutexattr_getpshared(const pthread_mutexattr_t *attr,
int *pshared);
int pthread_mutexattr_setpshared(pthread_mutexattr_t *attr,
int pshared);
Compile and link with
-pthread.
These functions get and set the process-shared attribute in a mutex attributes
object. This attribute must be appropriately set to ensure correct, efficient
operation of a mutex created using this attributes object.
The process-shared attribute can have one of the following values:
- PTHREAD_PROCESS_PRIVATE
- Mutexes created with this attributes object are to be shared only among
threads in the same process that initialized the mutex. This is the
default value for the process-shared mutex attribute.
- PTHREAD_PROCESS_SHARED
- Mutexes created with this attributes object can be shared between any
threads that have access to the memory containing the object, including
threads in different processes.
pthread_mutexattr_getpshared() places the value of the process-shared
attribute of the mutex attributes object referred to by
attr in the
location pointed to by
pshared.
pthread_mutexattr_setpshared() sets the value of the process-shared
attribute of the mutex attributes object referred to by
attr to the
value specified in
pshared.
If
attr does not refer to an initialized mutex attributes object, the
behavior is undefined.
On success, these functions return 0. On error, they return a positive error
number.
pthread_mutexattr_setpshared() can fail with the following errors:
- EINVAL
- The value specified in pshared is invalid.
- ENOTSUP
- pshared is PTHREAD_PROCESS_SHARED but the implementation
does not support process-shared mutexes.
POSIX.1-2001, POSIX.1-2008.
pthread_mutexattr_init(3),
pthreads(7)