 failure, a non-zero error code is
returned. 
</P>
<H2><A HREF="#toc5" NAME="sect5">Errors</A></H2>
<P>The <B>pthread_sigmask</B> function returns the following error
codes on error: 
</P>
<DL>
	<DL>
		<DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EINVAL</B> 
		</DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
		<I>how</I> is not one of <B>SIG_SETMASK</B>, <B>SIG_BLOCK</B>, or
		<B>SIG_UNBLOCK</B> 
		</DD></DL>
</DL>
<P>
The <B>pthread_kill</B> function returns the following error codes on
