pthread_mutex_init(3)pthread_mutex_init(3)NAMEpthread_mutex_init - Initializes a mutex
const pthread_mutexattr_t *attr );
DECthreads POSIX 1003.1c Library (libpthread.so)
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
IEEE Std 1003.1c-1995, POSIX System Application Program Interface
Mutex to be initialized. Mutex attributes object that defines the
characteristics of the mutex to be initialized.
This routine initializes a mutex with the attributes specified by the
mutex attributes object specified in the attr argument. A mutex is a
synchronization object that allows multiple threads to serialize their
access to shared data.
The mutex is initialized and set to the unlocked state. If attr is set
to NULL, the default mutex attributes are used. The pthread_mutex‐
attr_settype(3) routine can be used to specify the type of mutex that
is created (normal, recursive, or errorcheck).
Use the PTHREAD_MUTEX_INITIALIZER macro to statically initialize a
mutex without calling this routine. Statically initialized mutexes need
not be destroyed using pthread_mutex_destroy(3). Use this macro as fol‐
pthread_mutex_t mutex= PTHREAD_MUTEX_INITIALIZER
Only normal mutexes can be statically initialized.
A mutex is a resource of the process, not part of any particular
thread. A mutex is neither destroyed nor unlocked automatically when
any thread exits. If a mutex is allocated on a stack, static initial‐
izers cannot be used on the mutex.
If an error condition occurs, this routine returns an integer value
indicating the type of error, the mutex is not initialized, and the
contents of mutex are undefined. Possible return values are as follows:
Successful completion. The system lacks the necessary resources to
initialize the mutex. The implementation has detected an attempt to
reinitialize the mutex (a previously initialized, but not yet destroyed
mutex). The value specified by mutex is not a valid mutex. Insuffi‐
cient memory exists to initialize the mutex. The caller does not have
privileges to perform the operation.
Functions: pthread_mutexattr_init(3), pthread_mutexattr_gettype(3),
pthread_mutexattr_settype(3), pthread_mutex_lock(3), pthread_mutex_try‐
Manuals: Guide to DECthreads and Programmer's Guide