AC_FUNC_MEMMOVE
, 

2002-09-26

Rüdiger Kuhlmann <info@ruediger-kuhlmann.de>

AllPermissive
Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. Users of this software should generally follow the principles of the MIT License includings its disclaimer.

cryp.to ac-archive's C Support (released)

Checks for a memmove that can handle overlaps correctly. If no working memmove is found, request a replacement and warn the user about it.

AC_DEFUN([AC_FUNC_MEMMOVE],
[AC_CHECK_FUNCS(memmove)
AC_MSG_CHECKING(for working memmove)
AC_CACHE_VAL(ac_cv_have_working_memmove,
[AC_TRY_RUN(
[#include <stdio.h>

int main(void)
{
    char buf[10];
    strcpy (buf, "01234567");
    memmove (buf, buf + 2, 3);
    if (strcmp (buf, "23434567"))
        exit (1);
    strcpy (buf, "01234567");
    memmove (buf + 2, buf, 3);
    if (strcmp (buf, "01012567"))
        exit (1);
    exit (0);
}], ac_cv_have_working_memmove=yes, ac_cv_have_working_memmove=no, ac_cv_have_working_memmove=cross)])
AC_MSG_RESULT([$ac_cv_have_working_memmove])
if test x$ac_cv_have_working_memmove != "xyes"; then
  AC_LIBOBJ(memmove)
  AC_MSG_WARN([Replacing missing/broken memmove.])
  AC_DEFINE(PREFER_PORTABLE_MEMMOVE, 1, "enable replacement memmove if system memmove is broken or missing")
fi])