Re: warning in 2.4.1pre10

[Peter Samuelson <peter@cadcamlab.org>]

[J. A. Magallon]
> I know Linux will never be compiled with any other thing than
> gcc. But what I do not understand is why if there is a standard C way
> of doing something you have to use an strange extension of gcc.

__attribute__((noreturn)) may do other things besides suppress the "no
return from non-void function" warning.  The gcc manual gives two
additional reasons for it:

          void fatal () __attribute__ ((noreturn));

     The `noreturn' keyword tells the compiler to assume that `fatal'
     cannot return.  It can then optimize without regard to what would
     happen if `fatal' ever did return.  This makes slightly better
     code.  More importantly, it helps avoid spurious warnings of
     uninitialized variables.

Thus it is not a workaround, it is a way to give the optimizer extra
information.  Standard C cannot express this assertion, to my
knowledge, so if you stick with ISO you get suboptimal code.

>From another viewpoint: the 'return 0', though syntactically correct,
would be misleading -- it will never be executed and we know it.  Using
__attribute__((noreturn)) reflects reality, which is usually a good
thing for coding style.  (Whoops, I said "coding style".(: )


> Same happens with 'return' and 'break'. You type the same to add a
> '/* DO NOT REMEMBER THE PRECISE COMMENT */' to shut up the compiler
> instead of just writing
> case X:
> 	...
> 	return xxx;
> 	break;
> 
> ???
> Size optimization for the couple of bytes of the jump in return or break ?

Sorry, I don't follow your point here..

Peter
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