~drizzle-trunk/drizzle/development

AC_DEFUN([DRIZZLE_FUNC_ALLOCA],

[

# Since we have heard that alloca fails on IRIX never define it on a

# SGI machine

if test ! "$host_vendor" = "sgi"

then

 AC_REQUIRE_CPP()dnl Set CPP; we run AC_EGREP_CPP conditionally.

 # The Ultrix 4.2 mips builtin alloca declared by alloca.h only works

 # for constant arguments.  Useless!

 AC_CACHE_CHECK([for working alloca.h], ac_cv_header_alloca_h,

 [AC_TRY_LINK([#include <alloca.h>], [char *p = alloca(2 * sizeof(int));],

   ac_cv_header_alloca_h=yes, ac_cv_header_alloca_h=no)])

 if test "$ac_cv_header_alloca_h" = "yes"

 then

	AC_DEFINE(HAVE_ALLOCA, 1)

 fi

 AC_CACHE_CHECK([for alloca], ac_cv_func_alloca_works,

 [AC_TRY_LINK([

 #ifdef __GNUC__

 # define alloca __builtin_alloca

 #else

 # if HAVE_ALLOCA_H

 #  include <alloca.h>

 # else

 #  ifdef _AIX

  #pragma alloca

 #  else

 #   ifndef alloca /* predefined by HP cc +Olibcalls */

 char *alloca ();

 #   endif

 #  endif

 # endif

 #endif

 ], [char *p = (char *) alloca(1);],

   ac_cv_func_alloca_works=yes, ac_cv_func_alloca_works=no)])

 if test "$ac_cv_func_alloca_works" = "yes"; then

   AC_DEFINE([HAVE_ALLOCA], [1], [If we have a working alloca() implementation])

 fi

 if test "$ac_cv_func_alloca_works" = "no"; then

   # The SVR3 libPW and SVR4 libucb both contain incompatible functions

   # that cause trouble.  Some versions do not even contain alloca or

   # contain a buggy version.  If you still want to use their alloca,

   # use ar to extract alloca.o from them instead of compiling alloca.c.

   ALLOCA=alloca.o

   AC_DEFINE(C_ALLOCA, 1)

 fi

 AC_SUBST(ALLOCA)dnl

else

 AC_MSG_RESULT("Skipped alloca tests")

fi

])