gnulib/import/m4/dup.m4

   1 # dup.m4 serial 4
   2 dnl Copyright (C) 2011-2016 Free Software Foundation, Inc.
   3 dnl This file is free software; the Free Software Foundation
   4 dnl gives unlimited permission to copy and/or distribute it,
   5 dnl with or without modifications, as long as this notice is preserved.
   6
   7 AC_DEFUN([gl_FUNC_DUP],
   8 [
   9   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
  10   AC_REQUIRE([gl_MSVC_INVAL])
  11   if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
  12     REPLACE_DUP=1
  13   fi
  14   dnl Replace dup() for supporting the gnulib-defined fchdir() function,
  15   dnl to keep fchdir's bookkeeping up-to-date.
  16   m4_ifdef([gl_FUNC_FCHDIR], [
  17     gl_TEST_FCHDIR
  18     if test $HAVE_FCHDIR = 0; then
  19       REPLACE_DUP=1
  20     fi
  21   ])
  22   AC_CACHE_CHECK([whether dup works], [gl_cv_func_dup_works],
  23     [AC_RUN_IFELSE(
  24       [AC_LANG_PROGRAM([[#include <unistd.h>
  25                          #include <fcntl.h>
  26                          #include <errno.h>]],
  27          [[/* On OS/2 kLIBC, dup does not work on a directory fd.  */
  28            int fd = open (".", O_RDONLY);
  29            return fd < 0 ? 1 : dup (fd) < 0 ? 2 : 0;
  30          ]])
  31       ],
  32       [gl_cv_func_dup_works=yes],
  33       [gl_cv_func_dup_works=no],
  34       [gl_cv_func_dup_works='guessing yes'])
  35     ])
  36   case "$gl_cv_func_dup_works" in
  37     *yes) ;;
  38     *)
  39       REPLACE_DUP=1
  40       ;;
  41   esac
  42 ])
  43
  44 # Prerequisites of lib/dup.c.
  45 AC_DEFUN([gl_PREREQ_DUP], [:])