Silence buildbot warnings about unused results

This ignores the results of the two writes in sigint handlers even
harder than before.

While my libc lacks the declarations that trigger these warnings, this
can be tested by adding the following to notmuch.h:

__attribute__((warn_unused_result))
ssize_t write(int fd, const void *buf, size_t count);

diff --git a/compat/compat.h b/compat/compat.h
index 7767fe84a68580dbd2d2953f99645eda81403cac..b2e27368cf0690701c81b692fc0f9dce4c7216f4 100644 (file)
--- a/compat/compat.h
+++ b/compat/compat.h
@@ -46,6 +46,14 @@ getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp);
 char* strcasestr(const char *haystack, const char *needle);
 #endif /* !HAVE_STRCASESTR */
 
 char* strcasestr(const char *haystack, const char *needle);
 #endif /* !HAVE_STRCASESTR */
 

+/* Silence gcc warnings about unused results.  These warnings exist
+ * for a reason; any use of this needs to be justified. */
+#ifdef __GNUC__
+#define IGNORE_RESULT(x) ({ __typeof__(x) __z = (x); (void)(__z = __z); })
+#else /* !__GNUC__ */
+#define IGNORE_RESULT(x) x
+#endif /* __GNUC__ */
+

 #ifdef __cplusplus
 }
 #endif
 #ifdef __cplusplus
 }
 #endif

diff --git a/notmuch-new.c b/notmuch-new.c
index 3512de727734ad48025f3f88972587fed91d838b..a569a54454560ef33cb3fdad41c484658f514f35 100644 (file)
--- a/notmuch-new.c
+++ b/notmuch-new.c
@@ -67,7 +67,11 @@ handle_sigint (unused (int sig))
 {
     static char msg[] = "Stopping...         \n";
 
 {
     static char msg[] = "Stopping...         \n";
 

-    (void) write(2, msg, sizeof(msg)-1);
+    /* This write is "opportunistic", so it's okay to ignore the
+     * result.  It is not required for correctness, and if it does
+     * fail or produce a short write, we want to get out of the signal
+     * handler as quickly as possible, not retry it. */
+    IGNORE_RESULT (write (2, msg, sizeof(msg)-1));

     interrupted = 1;
 }
 
     interrupted = 1;
 }
 

diff --git a/notmuch-tag.c b/notmuch-tag.c
index 292c5da3f824a222caceed290109cabed40e959c..44fd61f6811db84d8e437f37247404140764556a 100644 (file)
--- a/notmuch-tag.c
+++ b/notmuch-tag.c
@@ -26,7 +26,12 @@ static void
 handle_sigint (unused (int sig))
 {
     static char msg[] = "Stopping...         \n";
 handle_sigint (unused (int sig))
 {
     static char msg[] = "Stopping...         \n";

-    (void) write(2, msg, sizeof(msg)-1);
+
+    /* This write is "opportunistic", so it's okay to ignore the
+     * result.  It is not required for correctness, and if it does
+     * fail or produce a short write, we want to get out of the signal
+     * handler as quickly as possible, not retry it. */
+    IGNORE_RESULT (write (2, msg, sizeof(msg)-1));

     interrupted = 1;
 }
 
     interrupted = 1;
 }