1pthread_rwlock_wrlock(3C)Standard C Library Functionspthread_rwlock_wrlock(3C)
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NAME

6       pthread_rwlock_wrlock,  pthread_rwlock_trywrlock  -  lock or attempt to
7       lock read-write lock object for writing
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SYNOPSIS

10       cc -mt [ flag... ] file... -lpthread [ library... ]
11       #include <pthread.h>
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13       int pthread_rwlock_wrlock(pthread_rwlock_t *rwlock);
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16       int pthread_rwlock_trywrlock(pthread_rwlock_t *rwlock);
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DESCRIPTION

20       The pthread_rwlock_wrlock() function applies a write lock to the  read-
21       write  lock referenced by rwlock. The calling thread acquires the write
22       lock if no other thread (reader or writer) holds  the  read-write  lock
23       rwlock. Otherwise, the thread blocks until it can acquire the lock.
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26       The  pthread_rwlock_trywrlock()  function applies a write lock like the
27       pthread_rwlock_wrlock() function, with the exception that the  function
28       fails if any thread currently holds rwlock (for reading or writing).
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31       Writers  are  favored over readers of the same priority to avoid writer
32       starvation. See pthread_rwlock_rdlock(3C).
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35       Results are undefined if any of these  functions  are  called  with  an
36       uninitialized read-write lock.
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39       If  a signal is delivered to a thread waiting for a read-write lock for
40       writing, upon return from the signal handler the thread resumes waiting
41       for the read-write lock for writing as if it was not interrupted.
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RETURN VALUES

44       If  successful,  the pthread_rwlock_wrlock() function returns 0. Other‐
45       wise, an error number is returned to indicate the error.
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48       The pthread_rwlock_trywrlock() function returns 0 if the lock for writ‐
49       ing  on  the  read-write  lock object referenced by rwlock is acquired.
50       Otherwise an error number is returned to indicate the error.
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ERRORS

53       The pthread_rwlock_wrlock() function will fail if:
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55       EDEADLK    The current thread already  owns  the  read-write  lock  for
56                  writing or reading.
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60       The pthread_rwlock_trywrlock() function will fail if:
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62       EBUSY    The  read-write lock could not be acquired for writing because
63                it was already locked for reading or writing.
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ATTRIBUTES

67       See  attributes(5) for descriptions of the following attributes:
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72       ┌─────────────────────────────┬─────────────────────────────┐
73       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
74       ├─────────────────────────────┼─────────────────────────────┤
75       │Interface Stability          │Standard                     │
76       ├─────────────────────────────┼─────────────────────────────┤
77       │MT-Level                     │MT-Safe                      │
78       └─────────────────────────────┴─────────────────────────────┘
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SEE ALSO

81       pthread_rwlock_init(3C),   pthread_rwlock_unlock(3C),   pthread_rwlock‐
82       attr_init(3C), pthread_rwlock_rdlock(3C), attributes(5), standards(5)
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86SunOS 5.11                        23 Mar 2005        pthread_rwlock_wrlock(3C)
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