[PATCH 2/2] Silence buildbot warnings about unused results

[Austin Clements]

Quoth David Edmondson on Jan 19 at  7:23 am:
> On Wed, 18 Jan 2012 19:40:11 -0500, Austin Clements  
> wrote:
> > +/* See handle_sigint in notmuch-new.c for the justification for
> > + * ignoring write's result. */
> > +IGNORE_RESULT (write (2, msg, sizeof(msg)-1));
> 
> Just include the comment in both places. Someone will work over the code
> in notmuch-new.c and we'll lose it.

Done.

> Then, +1.

[PATCH 2/2] Silence buildbot warnings about unused results

[David Edmondson]

On Wed, 18 Jan 2012 19:40:11 -0500, Austin Clements  wrote:
> +/* See handle_sigint in notmuch-new.c for the justification for
> + * ignoring write's result. */
> +IGNORE_RESULT (write (2, msg, sizeof(msg)-1));

Just include the comment in both places. Someone will work over the code
in notmuch-new.c and we'll lose it.

Then, +1.
-- next part --
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 197 bytes
Desc: not available
URL: 

Re: [PATCH 2/2] Silence buildbot warnings about unused results

[Austin Clements]

Quoth David Edmondson on Jan 19 at  7:23 am:
 On Wed, 18 Jan 2012 19:40:11 -0500, Austin Clements amdra...@mit.edu wrote:
  +/* See handle_sigint in notmuch-new.c for the justification for
  + * ignoring write's result. */
  +IGNORE_RESULT (write (2, msg, sizeof(msg)-1));
 
 Just include the comment in both places. Someone will work over the code
 in notmuch-new.c and we'll lose it.

Done.

 Then, +1.
___
notmuch mailing list
notmuch@notmuchmail.org
http://notmuchmail.org/mailman/listinfo/notmuch

[PATCH 2/2] Silence buildbot warnings about unused results

[Austin Clements]

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);
---
 compat/compat.h |8 
 notmuch-new.c   |6 +-
 notmuch-tag.c   |5 -
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/compat/compat.h b/compat/compat.h
index 7767fe8..b2e2736 100644
--- 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 */

+/* 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
diff --git a/notmuch-new.c b/notmuch-new.c
index 3512de7..a569a54 100644
--- a/notmuch-new.c
+++ b/notmuch-new.c
@@ -67,7 +67,11 @@ 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;
 }

diff --git a/notmuch-tag.c b/notmuch-tag.c
index 292c5da..1564182 100644
--- a/notmuch-tag.c
+++ b/notmuch-tag.c
@@ -26,7 +26,10 @@ static void
 handle_sigint (unused (int sig))
 {
 static char msg[] = "Stopping... \n";
-(void) write(2, msg, sizeof(msg)-1);
+
+/* See handle_sigint in notmuch-new.c for the justification for
+ * ignoring write's result. */
+IGNORE_RESULT (write (2, msg, sizeof(msg)-1));
 interrupted = 1;
 }

-- 
1.7.7.3

[PATCH 2/2] Silence buildbot warnings about unused results

[Austin Clements]

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);
---
 compat/compat.h |8 
 notmuch-new.c   |6 +-
 notmuch-tag.c   |5 -
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/compat/compat.h b/compat/compat.h
index 7767fe8..b2e2736 100644
--- 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 */
 
+/* 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
diff --git a/notmuch-new.c b/notmuch-new.c
index 3512de7..a569a54 100644
--- a/notmuch-new.c
+++ b/notmuch-new.c
@@ -67,7 +67,11 @@ 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;
 }
 
diff --git a/notmuch-tag.c b/notmuch-tag.c
index 292c5da..1564182 100644
--- a/notmuch-tag.c
+++ b/notmuch-tag.c
@@ -26,7 +26,10 @@ static void
 handle_sigint (unused (int sig))
 {
 static char msg[] = Stopping... \n;
-(void) write(2, msg, sizeof(msg)-1);
+
+/* See handle_sigint in notmuch-new.c for the justification for
+ * ignoring write's result. */
+IGNORE_RESULT (write (2, msg, sizeof(msg)-1));
 interrupted = 1;
 }
 
-- 
1.7.7.3

___
notmuch mailing list
notmuch@notmuchmail.org
http://notmuchmail.org/mailman/listinfo/notmuch

Re: [PATCH 2/2] Silence buildbot warnings about unused results

[David Edmondson]

On Wed, 18 Jan 2012 19:40:11 -0500, Austin Clements amdra...@mit.edu wrote:
 +/* See handle_sigint in notmuch-new.c for the justification for
 + * ignoring write's result. */
 +IGNORE_RESULT (write (2, msg, sizeof(msg)-1));

Just include the comment in both places. Someone will work over the code
in notmuch-new.c and we'll lose it.

Then, +1.


pgpWXU9Y5mX3J.pgp
Description: PGP signature
___
notmuch mailing list
notmuch@notmuchmail.org
http://notmuchmail.org/mailman/listinfo/notmuch