pthread_rwlockattr_getpshared, pthread_rwlockattr_setpshared - get and set the process-shared attribute of the read-write lock attributes object
[TSH] #include <pthread.h>
int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t
*restrict attr, int *restrict pshared);
int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr,
The pthread_rwlockattr_getpshared() function shall obtain the value of the process-shared attribute from the initialized attributes object referenced by attr. The pthread_rwlockattr_setpshared() function shall set the process-shared attribute in an initialized attributes object referenced by attr.
The process-shared attribute shall be set to PTHREAD_PROCESS_SHARED to permit a read-write lock to be operated upon by any thread that has access to the memory where the read-write lock is allocated, even if the read-write lock is allocated in memory that is shared by multiple processes. If the process-shared attribute is PTHREAD_PROCESS_PRIVATE, the read-write lock shall only be operated upon by threads created within the same process as the thread that initialized the read-write lock; if threads of differing processes attempt to operate on such a read-write lock, the behavior is undefined. The default value of the process-shared attribute shall be PTHREAD_PROCESS_PRIVATE.
Additional attributes, their default values, and the names of the associated functions to get and set those attribute values are implementation-defined.
The behavior is undefined if the value specified by the attr argument to pthread_rwlockattr_getpshared() or pthread_rwlockattr_setpshared() does not refer to an initialized read-write lock attributes object.
Upon successful completion, the pthread_rwlockattr_getpshared() function 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.
If successful, the pthread_rwlockattr_setpshared() function shall return zero; otherwise, an error number shall be returned to indicate the error.
The pthread_rwlockattr_setpshared() function may fail if:
- 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].
First released in Issue 5.
The following changes are made for alignment with IEEE Std 1003.1j-2000:
The margin code in the SYNOPSIS is changed to THR TSH to indicate that the functionality is now part of the Threads option (previously it was part of the Read-Write Locks option in IEEE Std 1003.1j-2000 and also part of the XSI extension).
The DESCRIPTION notes that additional attributes are implementation-defined.
The SEE ALSO section is updated.
The restrict keyword is added to the pthread_rwlockattr_getpshared() prototype for alignment with the ISO/IEC 9899:1999 standard.
The pthread_rwlockattr_getpshared() and pthread_rwlockattr_setpshared() functions are moved from the Threads option.
The [EINVAL] error for an uninitialized read-write lock attributes object is removed; this condition results in undefined behavior.
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