Hi Paul,
> I thought we had established that in some cases one should apply both
> _Noreturn and __attribute__ ((__noreturn__)) to the same declaration? I
> don't see that in this module.
Apparently we've been thinking at different solutions of the clang problem
(which, for type checking / assignment purposes, considers _Noreturn to
be different from __attribute__((__noreturn__))).
My solution in the proposed noreturn.h is to
#define _GL_NORETURN_FUNC __attribute__ ((__noreturn__))
#define _GL_NORETURN_FUNCPTR __attribute__ ((__noreturn__))
in this case. So clang won't warn.
You have been thinking of this?
#define _GL_NORETURN_FUNC _Noreturn
#define _GL_NORETURN_FUNCPTR _Noreturn __attribute__ ((__noreturn__))
> Also, I hope we're not envisioning a lot of replacement of _Noreturn
> with _GL_NORETURN_FUNC in other modules.
No, most of these functions (dfaerror, openat_save_fail, _Exit, xalloc_die, ...)
are not likely to be stored in function pointers.
> As I understand it,
> _GL_NORETURN_FUNC is needed only for functions that one wants to take
> addresses of, and to store these addresses in _GL_NORETURN_FUNCPTR
> variables. Most existing modules don't need to do this, and so can
> continue to use _Noreturn. This point should be made in the comments.
Good point. And for C++ support (other than g++ and MSVC) as well. I'm squashing
in this comment change:
--- a/lib/noreturn.h
+++ b/lib/noreturn.h
@@ -29,6 +29,16 @@
_GL_NORETURN_FUNC is for use in function declarations and function
definitions.
_GL_NORETURN_FUNCPTR is for use on function pointers.
+
+ Comparison of this file with <stdnoreturn.h>:
+ <stdnoreturn.h> defines a macro (or keyword) _Noreturn that declares
+ a function to be non-returning. _Noreturn is only for use in function
+ declarations and function definitions.
+ Therefore, if the non-returning functions you have to declare are unlikely
+ to be accessed through function pointers, and if the efficiency with C++
+ compilers other than g++, clang, MSVC++ is not an issue to you, you can use
+ module 'stdnoreturn' instead of this one, and _Noreturn instead of
+ _GL_NORETURN_FUNC.
*/
/* Declares that a function is nonreturning.
