error_errno: use constant return similar to error()

peff · gitster · commit 4df5e9186749 · 2016-08-31T11:11:54.000-07:00
Commit e208f9c (make error()'s constant return value more visible, 2012-12-15) introduced some macro trickery to make the constant return from error() more visible to callers, which in turn can help gcc produce better warnings (and possibly even better code). Later, fd1d672 (usage.c: add warning_errno() and error_errno(), 2016-05-08) introduced another variant, and subsequent commits converted some uses of error() to error_errno(), losing the magic from e208f9c for those sites. As a result, compiling vcs-svn/svndiff.c with "gcc -O3" produces -Wmaybe-uninitialized false positives (at least with gcc 6.2.0). Let's give error_errno() the same treatment, which silences these warnings. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/git-compat-util.h b/git-compat-util.h
@@ -436,6 +436,7 @@ static inline int const_error(void)
 	return -1;
 }
 #define error(...) (error(__VA_ARGS__), const_error())
+#define error_errno(...) (error_errno(__VA_ARGS__), const_error())
 #endif
 
 extern void set_die_routine(NORETURN_PTR void (*routine)(const char *err, va_list params));
diff --git a/usage.c b/usage.c
@@ -148,6 +148,7 @@ void NORETURN die_errno(const char *fmt, ...)
 	va_end(params);
 }
 
+#undef error_errno
 int error_errno(const char *fmt, ...)
 {
 	char buf[1024];

Original file line number	Diff line number	Diff line change
`@@ -436,6 +436,7 @@ static inline int const_error(void)`
`436`	`436`	`return -1;`
`437`	`437`	`}`
`438`	`438`	`#define error(...) (error(__VA_ARGS__), const_error())`
	`439`	`+#define error_errno(...) (error_errno(__VA_ARGS__), const_error())`
`439`	`440`	`#endif`
`440`	`441`
`441`	`442`	`extern void set_die_routine(NORETURN_PTR void (routine)(const char err, va_list params));`
Original file line number	Diff line number	Diff line change
`@@ -148,6 +148,7 @@ void NORETURN die_errno(const char *fmt, ...)`
`148`	`148`	`va_end(params);`
`149`	`149`	`}`
`150`	`150`
	`151`	`+#undef error_errno`
`151`	`152`	`int error_errno(const char *fmt, ...)`
`152`	`153`	`{`
`153`	`154`	`char buf[1024];`