[PATCH] Fix -Wunused-but-set-variable compiler warnings in tevent_signal.c

Martin Schwenke martin at meltin.net
Wed Nov 9 17:09:44 MST 2011

The results of some read(2) and write(2) calls are assigned into a
variable that is never used.  Presumably this used to avoid compiler
warnings or similar.

However, from (approximately) GCC 4.6 this produces some warnings:

  [ 609/3910] Compiling lib/tevent/tevent_signal.c
  ../lib/tevent/tevent_signal.c: In function
  ‘tevent_common_signal_handler’: ../lib/tevent/tevent_signal.c:85:10:
  warning: variable ‘res’ set but not used
  [-Wunused-but-set-variable] ../lib/tevent/tevent_signal.c: In
  function ‘signal_pipe_handler’: ../lib/tevent/tevent_signal.c:183:10:
  warning: variable ‘res’ set but not used [-Wunused-but-set-variable]

The simplest thing to do is remove the variables and cast the function
return to void.  There is already a comment above each call.

Signed-off-by: Martin Schwenke <martin at meltin.net>

diff --git a/lib/tevent/tevent_signal.c b/lib/tevent/tevent_signal.c
index b790859..fabe72c 100644
--- a/lib/tevent/tevent_signal.c
+++ b/lib/tevent/tevent_signal.c
@@ -82,7 +82,6 @@ static uint32_t tevent_sig_count(struct
tevent_sigcounter s) static void tevent_common_signal_handler(int
signum) {
 	char c = 0;
-	ssize_t res;
 	struct tevent_common_signal_list *sl;
 	struct tevent_context *ev = NULL;
 	int saved_errno = errno;
@@ -95,7 +94,7 @@ static void tevent_common_signal_handler(int signum)
 		if (sl->se->event_ctx && sl->se->event_ctx != ev) {
 			ev = sl->se->event_ctx;
 			/* doesn't matter if this pipe overflows */
-			res = write(ev->pipe_fds[1], &c, 1);
+			(void) write(ev->pipe_fds[1], &c, 1);
@@ -180,9 +179,8 @@ static void signal_pipe_handler(struct
tevent_context *ev, struct tevent_fd *fde uint16_t flags, void
*_private) {
 	char c[16];
-	ssize_t res;
 	/* its non-blocking, doesn't matter if we read too much */
-	res = read(fde->fd, c, sizeof(c));
+	(void) read(fde->fd, c, sizeof(c));

peace & happiness,

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