VMS Help POSIX Threads, TIS routines, tis_write_trylock  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Attempts to acquire a read-write lock for write access.

1 - C Binding

    #include <tis.h>

    int
    tis_write_trylock (
             tis_rwlock_t   *lock);

2 - Arguments

 lock

    Address of the read-write lock to be acquired for write access.

3 - Description

    This routine attempts to acquire a read-write lock for write
    access. The routine attempts to immediately acquire the lock.
    If the lock is acquired, zero (0) is returned. If the lock is
    held by another thread (for either read or write access), [EBUSY]
    is returned and the calling thread does not wait for the write-
    access lock to be acquired.

    Note that it is a coding error to attempt to acquire the lock
    for write access if the lock is already held by the calling
    thread. (However, this routine returns [EBUSY] anyway, because
    no ownership error-checking takes place.)

4 - Return Values

    If an error condition occurs, this routine returns an integer
    value indicating the type of error. Possible return values are as
    follows:

    Return      Description

    0           Successful completion, the lock is acquired for write
                access.
    [EBUSY]     The lock was not acquired for write access, as it is
                already held by another thread.
    [EINVAL]    The value specified by lock is not a valid read-write
                lock.

5 - Associated Routines

       tis_read_lock()
       tis_read_trylock()
       tis_read_unlock()
       tis_rwlock_destroy()
       tis_rwlock_init()
       tis_write_lock()
       tis_write_unlock()