ck</B> ,
<B>pthread_rwlock_timedwrlock</B> , <B>pthread_rwlock_tryrdlock</B> ,
<B>pthread_rwlock_trywrlock</B> , <B>pthread_rwlock_unlock</B> , or
<B>pthread_rwlock_wrlock</B> is undefined. 
</P>
<P><B>PThreads4W</B> defines <B>_POSIX_READER_WRITER_LOCKS</B> in
pthread.h as 200112L to indicate that the reader/writer routines are
implemented and may be used.</P>
<H2><A HREF="#toc3" NAME="sect3">Return Value</A></H2>
<P>If successful, the <B>pthread_rwlock_destroy</B> and
<B>pthread_rwlock_init</B> functions 