Returns the value of the kind attribute of a mutex attributes object.
Threads Library (libpthreads.a)
The pthread_mutexattr_getkind_np subroutine returns the value of the kind attribute of the mutex attributes object attr. This attribute specifies the kind of the mutex created with this attributes object. It may have one of the following values:
Item | Description |
---|---|
MUTEX_FAST_NP | Denotes a fast mutex. A fast mutex can be locked only once. If the same thread unlocks twice the same fast mutex, the thread will deadlock. Any thread can unlock a fast mutex. A fast mutex is not compatible with the priority inheritance protocol. |
MUTEX_RECURSIVE_NP | Denotes a recursive mutex. A recursive mutex can be locked more than once by the same thread without causing that thread to deadlock. The thread must then unlock the mutex as many times as it locked it. Only the thread that locked a recursive mutex can unlock it. A recursive mutex must not be used with condition variables. |
MUTEX_NONRECURSIVE_NP | Denotes the default non-recursive POSIX compliant mutex. |
This subroutine is not POSIX compliant and is provided only for compatibility with DCE threads. It should not be used when writing new applications.
Item | Description |
---|---|
attr | Specifies the mutex attributes object. |
kind | Points to where the kind attribute value will be stored. |
Upon successful completion, the value of the kind attribute is returned via the kind parameter, and 0 is returned. Otherwise, an error code is returned.
The pthread_mutexattr_getkind_np subroutine is unsuccessful if the following is true:
Item | Description |
---|---|
EINVAL | The attr parameter is not valid. |