--- Begin Message ---
|
Subject: |
_AC_COMPUTE_INT forgets to include stdio.h, stdlib.h |
|
Date: |
Thu, 13 Sep 2001 16:54:34 +0200 (CEST) |
Hi,
An _AC_COMPUTE_INT failure was reported to me, caused by the lack of
<stdio.h> by an autoconf generated snippet that uses 'FILE'.
Here is the input:
====================== configure.in ======================
AC_INIT(configure.in)
AC_CHECK_SIZEOF([wchar_t], [], [#include <wchar.h>])
_AC_COMPUTE_INT([EILSEQ], ac_cv_decl_EILSEQ, [
#include <errno.h>
#include <wchar.h>
])
AC_OUTPUT
==========================================================
Call 'autoconf' (version 2.52), you will see that the generated
configure file contains the two following test programs.
==========================================================
#line 1808 "configure"
#include "confdefs.h"
#include <wchar.h>
int
main ()
{
FILE *f = fopen ("conftest.val", "w");
if (!f)
exit (1);
fprintf (f, "%d", (sizeof (wchar_t)));
fclose (f);
;
return 0;
}
==========================================================
#line 2009 "configure"
#include "confdefs.h"
#include <errno.h>
#include <wchar.h>
int
main ()
{
FILE *f = fopen ("conftest.val", "w");
if (!f)
exit (1);
fprintf (f, "%d", (EILSEQ));
fclose (f);
;
return 0;
}
==========================================================
There are three bugs here:
1) The code should include <stdio.h>, for FILE.
2) The code should include <stdlib.h>, for exit(). This matters when
the C compiler is actually a C++ compiler: CC="gcc" CFLAGS="-x c++".
3) The printf argument could be of type 'long' or 'size_t'. Before
passing it to printf, you need to cast it to 'int', to avoid problems
on 64-bit platforms.
Below is a patch that changes the produced snippet to read as follows.
==========================================================
#line 1808 "configure"
#include "confdefs.h"
#include <wchar.h>
int conftestval () { return (sizeof (wchar_t)); }
#include <stdio.h>
#include <stdlib.h>
int
main ()
{
FILE *f = fopen ("conftest.val", "w");
if (!f)
exit (1);
fprintf (f, "%d", conftestval ());
fclose (f);
;
return 0;
}
==========================================================
2001-09-13 Bruno Haible <address@hidden>
* aclang.m4 (AC_LANG_INT_SAVE(C)): Always include <stdio.h> and
<stdlib.h>. Evaluate the expression in an extra function before
these includes. Call fprintf "%d" only after ensuring the argument
is of type 'int'.
Reported by Wayne Chapeskie <address@hidden>.
*** aclang.m4.bak Wed Jul 18 14:47:34 2001
--- aclang.m4 Thu Sep 13 13:03:33 2001
***************
*** 423,436 ****
# AC_LANG_INT_SAVE(C)(PROLOGUE, EXPRESSION)
# -----------------------------------------
! # We need `stdio.h' to open a `FILE', so the prologue defaults to the
! # inclusion of `stdio.h'.
m4_define([AC_LANG_INT_SAVE(C)],
! [AC_LANG_PROGRAM([m4_default([$1], address@hidden:@include <stdio.h>])],
[FILE *f = fopen ("conftest.val", "w");
if (!f)
exit (1);
! fprintf (f, "%d", ($2));
fclose (f);])])
--- 423,439 ----
# AC_LANG_INT_SAVE(C)(PROLOGUE, EXPRESSION)
# -----------------------------------------
! # We need `stdio.h' to open a `FILE' and `stdlib.h' for 'exit'. But we include
! # them only after the EXPRESSION has been evaluated.
m4_define([AC_LANG_INT_SAVE(C)],
! [AC_LANG_PROGRAM([$1
! int conftestval () { return ($2); }
! @%:@include <stdio.h>
! @%:@include <stdlib.h>],
[FILE *f = fopen ("conftest.val", "w");
if (!f)
exit (1);
! fprintf (f, "%d", conftestval ());
fclose (f);])])
--- End Message ---