Re: [PATCH] test-raise: use _Noreturn

[Bruno Haible]

Paolo Bonzini wrote:
> exit is declared as a nonreturning built-in by GCC
> (devel/gcc/gcc/builtins.def):

Indeed, the fact that it's a built-in makes a difference:

========================== foo.c ================================
extern /*__attribute__ ((__noreturn__))*/ void exit (int);
static __attribute__ ((__noreturn__)) void handler (int sig)
{
  exit (0);
}
=================================================================

$ gcc -Wall -Wmissing-noreturn -c foo.c
$ gcc -Wall -Wmissing-noreturn -c foo.c -Dexit=otherfunc
foo.c: In function 'handler':
foo.c:5:1: warning: 'noreturn' function does return

This also answers Eric's question whether we should do something
in gnulib's <stdlib.h> replacement.

I'm applying Bernhard's patch, with comments.

> For non-GCC compilers I don't think we care about warnings, do we?

Right.

Bruno


2011-10-07  Bernhard Voelker  <address@hidden>

        raise tests: Avoid a GCC warning.
        * tests/test-raise.c (handler): Use _Noreturn.

--- a/tests/test-raise.c
+++ b/tests/test-raise.c
@@ -25,7 +25,10 @@ SIGNATURE_CHECK (raise, int, (int));
 
 #include "macros.h"
 
-static void
+/* It is safe to use _Noreturn here: exit() never returns, and GCC knows that
+   exit() is a non-returning function, even on platforms where its declaration
+   in <stdlib.h> does not have the 'noreturn' attribute.  */
+static _Noreturn void
 handler (int sig)
 {
   exit (0);
-- 
In memoriam Anna Politkovskaya <http://en.wikipedia.org/wiki/Anna_Politkovskaya>