Re: AC_FUNC_MALLOC

[Paul Eggert]

> From: Akim Demaille <address@hidden>
> Date: 29 Oct 2002 14:50:29 +0100
> 
> AFAIC, this macro is fine in Autoconf.  But I'm waiting for other
> opinions.

I think the macro is OK, since it encourages a programming style that
is easier to read and maintain, and which works just fine with glibc.
However, the documentation was misleading, so I installed this patch.

Note that I also changed "char *" to "void *".  "char *" does not
conform to the C standard.  I think the "char *" was there for
compatibility with some buggy pre-K&R C compilers, but I don't think
we need to worry about them any more, at least not in example code.

Index: autoconf.texi
===================================================================
RCS file: /cvsroot/autoconf/autoconf/doc/autoconf.texi,v
retrieving revision 1.705
retrieving revision 1.706
diff -p -u -r1.705 -r1.706
--- autoconf.texi       29 Oct 2002 13:07:19 -0000      1.705
+++ autoconf.texi       29 Oct 2002 20:22:54 -0000      1.706
@@ -3776,7 +3776,8 @@ If @code{lstat} behaves properly, define
 @cvindex malloc
 @c @fuindex malloc
 @prindex @code{malloc}
-If the @code{malloc} function works correctly (@samp{malloc (0)} returns a 
valid
+If the @code{malloc} function is compatible with the @acronym{GNU} C
+library @code{malloc} (i.e., @samp{malloc (0)} returns a valid
 pointer), define @code{HAVE_MALLOC} to 1.  Otherwise define
 @code{HAVE_MALLOC} to 0, ask for an @code{AC_LIBOBJ} replacement for
 @samp{malloc}, and define @code{malloc} to @code{rpl_malloc} so that the
@@ -3793,12 +3794,12 @@ the @samp{#undef malloc}):
 
 #include <sys/types.h>
 
-char *malloc ();
+void *malloc ();
 
 /* Allocate an N-byte block of memory from the heap.
    If N is zero, allocate a 1-byte block.  */
 
-char *
+void *
 rpl_malloc (size_t n)
 {
   if (n == 0)
@@ -3862,7 +3863,8 @@ If the obstacks are found, define @code{
 @cvindex realloc
 @c @fuindex realloc
 @prindex @code{realloc}
-If the @code{realloc} function works correctly (@samp{realloc (0, 0)} returns a
+If the @code{realloc} function is compatible with the @acronym{GNU} C
+library @code{realloc} (i.e., @samp{realloc (0, 0)} returns a
 valid pointer), define @code{HAVE_REALLOC} to 1.  Otherwise define
 @code{HAVE_REALLOC} to 0, ask for an @code{AC_LIBOBJ} replacement for
 @samp{realloc}, and define @code{realloc} to @code{rpl_realloc} so that
@@ -4584,7 +4586,7 @@ with the system's one, you should use:
 
 @example
 #if defined HAVE_DECL_MALLOC && !HAVE_DECL_MALLOC
-char *malloc (size_t *s);
+void *malloc (size_t *s);
 #endif
 @end example
 
@@ -5751,7 +5753,7 @@ include any header files containing clas
 #ifdef __cplusplus
 extern "C" void *malloc (size_t);
 #else
-char *malloc ();
+void *malloc ();
 #endif
 @end example