Re: implicit declaration of function 'utime' in trailing slashes test

[Bruno Haible]

> >>> conftest.c:491:23: error: implicit declaration of function 'utime' is 
> >>> invalid in C99 [-Werror,-Wimplicit-function-declaration]
> >>>                   if (!utime ("conftest.tmp/", NULL))
> >>>                        ^
> >>> 1 error generated.

Thanks for the report. Fixed through the patch below.

> ARM processors have different calling conventions for variadic and
> non-variadic functions, so the compiler must know before you call a
> function what type of function it is, and the way it knows that is
> by the function declaration.

This is well-known for 'float' parameters (for a long time, on most
platforms).

Do you happen to know other cases for which this is the case? I'm asking
in order to check GNU libffcall and libffi w.r.t. this situation.

Bruno


2021-01-23  Bruno Haible  <bruno@clisp.org>

        utime: Fix configure test (regression 2020-12-04).
        Reported by Ryan Schmidt <wget@ryandesign.com> via Tim Rühsen in
        <https://lists.gnu.org/archive/html/bug-gnulib/2021-01/msg00282.html>.
        * m4/utime.m4 (gl_FUNC_UTIME): In the test program, include <utime.h>,
        not <time.h>.

diff --git a/m4/utime.m4 b/m4/utime.m4
index 03df7b7..4ed4158 100644
--- a/m4/utime.m4
+++ b/m4/utime.m4
@@ -1,4 +1,4 @@
-# utime.m4 serial 3
+# utime.m4 serial 4
 dnl Copyright (C) 2017-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -34,7 +34,7 @@ AC_DEFUN([gl_FUNC_UTIME],
            AC_RUN_IFELSE(
              [AC_LANG_PROGRAM(
                [[#include <stddef.h>
-                 #include <time.h>
+                 #include <utime.h>
                ]],
                [[int result = 0;
                  if (!utime ("conftest.tmp/", NULL))