diff -up libpfm-3.4/examples/self_pipe.c.unused libpfm-3.4/examples/self_pipe.c
--- libpfm-3.4/examples/self_pipe.c.unused	2008-05-02 09:49:25.000000000 -0400
+++ libpfm-3.4/examples/self_pipe.c	2008-05-02 09:49:40.000000000 -0400
@@ -125,6 +125,7 @@ main(int argc, char **argv)
 	size_t len;
 	char *name;
 	char c = '0';
+	int nbytes;
 
 	/*
 	 * pass options to library (optional)
@@ -312,8 +313,8 @@ main(int argc, char **argv)
 	 * ping pong loop
 	 */
 	while(!quit) {
-		write(pr[1], "c", 1);
-		read(pw[0], &c, 1);	
+		nbytes = write(pr[1], "c", 1);
+		nbytes = read(pw[0], &c, 1);	
 	}
 
 	if (pfm_stop(ctx_fd))