Re: AC_FUNC_MALLOC, AC_FUNC_REALLOC and crossbuilding with mingw

[Keith Marshall]

Hi David,

On Sat, 2007-12-29 at 15:38 -0500, David Bruce wrote:
> I cross-build my native linux program for Windows using mingw.  I recently 
> ran 
> autoscan to see if my configure.ac was lacking anything that ought to be in 
> there, and the recommendations included adding AC_FUNC_MALLOC and 
> AC_FUNC_REALLOC.  These macros cause the cross-build to fail with errors 
> about "undefined reference to _rpl_malloc", etc.

Yes, I've noticed this too.

> The autoconf manual says 
> that the macros are supposed to enforce compatibility with GNU's malloc in 
> that 'malloc(0)' should return a valid pointer, and suggests a sort of 
> wrapper to accomplish this.
> 
> My question is whether I can safely comment out AC_FUNC_MALLOC and 
> AC_FUNC_REALLOC, because the program seems to build and run fine on both 
> platforms without these checks.

Well, MinGW just uses Microsnot's malloc() and realloc(), from
MSVCRT.dll.  AFAIK, these functions are compliant with the expectations
of AC_FUNC_MALLOC and AC_FUNC_REALLOC; certainly, when building natively
on Woe32, using MSYS, both these macros report that their associated
functions are acceptable.  The problem is, when cross-compiling, the
test code cannot be executed, to verify compliance.

I think you can safely disdense with these two tests, when
cross-compiling for a Woe32 host.

Regards,
Keith.