freopen-safer: new module * modules/freopen-safer: New module. * m4/stdio-safer.m4 (gl_FREOPEN_SAFER): New macro. * lib/freopen-safer.c (freopen_safer): New file. * lib/stdio-safer.h (freopen_safer): New declaration. * lib/stdio--.h (freopen): New override. * MODULES.html.sh (File stream based Input/Output): Mention it. * doc/posix-functions/freopen.texi (freopen): Mention pitfalls and freopen-safer module. * doc/posix-functions/stderr.texi (stderr): Likewise. * doc/posix-functions/stdin.texi (stdin): Likewise. * doc/posix-functions/stdout.texi (stdout): Likewise. * modules/freopen-safer-tests: New test. * tests/test-reopen-safer.c: New file. Signed-off-by: Eric Blake <ebb9@byu.net>

/* memmove.c -- copy memory.
   Copy LENGTH bytes from SOURCE to DEST.  Does not null-terminate.
   In the public domain.
   By David MacKenzie <djm@gnu.ai.mit.edu>.  */

#include <config.h>

#include <stddef.h>

void *
memmove (void *dest0, void const *source0, size_t length)
{
  char *dest = dest0;
  char const *source = source0;
  if (source < dest)
    /* Moving from low mem to hi mem; start at end.  */
    for (source += length, dest += length; length; --length)
      *--dest = *--source;
  else if (source != dest)
    {
      /* Moving from hi mem to low mem; start at beginning.  */
      for (; length; --length)
	*dest++ = *source++;
    }
  return dest0;
}