[RFC/AIX] xm-aix4.h - Remove alloca #pragma

[RFC/AIX] xm-aix4.h - Remove alloca #pragma

[Joel Brobecker]

config/xm-aix4.h contains the following definition:

| /* The IBM compiler requires this in order to properly compile alloca().  */
| #pragma alloca

I just checked with an IBM C compiler, and indeed, we need this pragma
or the link will fail.  Yuck! Can we solve this problem this way?

   . Add a check in configure to link a program using alloca.
   . If pass, we're done.
   . Try again with #pragma alloca
   . If pass, then define #USE_PRAGMA_ALLOCA, or HAVE_PRAGMA_ALLOCA
     or something like this
   . Some other ways to get alloca???
   . If fail, then abort configure, we need alloca.

Then add something like this in defs:

#ifdef USE_PRAGMA_ALLOCA
#pragma alloca
#endif

-- 
Joel

Re: [RFC/AIX] xm-aix4.h - Remove alloca #pragma

[Peter Schauer]

Could you please try to include malloc.h instead ?

> config/xm-aix4.h contains the following definition:
> 
> | /* The IBM compiler requires this in order to properly compile alloca().  */
> | #pragma alloca
> 
> I just checked with an IBM C compiler, and indeed, we need this pragma
> or the link will fail.  Yuck! Can we solve this problem this way?
> 
>    . Add a check in configure to link a program using alloca.
>    . If pass, we're done.
>    . Try again with #pragma alloca
>    . If pass, then define #USE_PRAGMA_ALLOCA, or HAVE_PRAGMA_ALLOCA
>      or something like this
>    . Some other ways to get alloca???
>    . If fail, then abort configure, we need alloca.
> 
> Then add something like this in defs:
> 
> #ifdef USE_PRAGMA_ALLOCA
> #pragma alloca
> #endif
> 
> -- 
> Joel
> 


-- 
Peter Schauer			Peter.Schauer@mytum.de

Re: [RFC/AIX] xm-aix4.h - Remove alloca #pragma

[Mark Kettenis]

   From: Peter Schauer <Peter.Schauer@mytum.de>
   Date: Sun, 8 Aug 2004 09:39:25 +0200 (CEST)

   Could you please try to include malloc.h instead ?

Including malloc.h is a bad idea.  Many modern systems have a #warning
in that file, which would kill -Werror compilation.

Anyway.  The whole alloca mess is pretty well sorted out in autoconf.
There is an AC_FUNC_ALLOCA macro and we're calling it in our
configure.in.  The necessary glue, include the #pragma alloca is in
defs.h (although it is arranges a little differently than the autoconf
manual suggests).  So I really think we can just scrap it.

Mark