renamed semaphore example

Author: vladak

threads.tex

@@ -1428,7 +1428,7 @@
 see page \pageref{NAMED_SEMAPHORES}), hence they are called unnamed.
 \item The semaphore functions adhere to the classical UNIX semantics --
 they return -1 on error and set \texttt{errno}.
-\item Example: \example{semaphores/sem.c}
+\item Example: \example{semaphores/posix-unnamed-sem.c}
 \end{itemize}
 
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