2 dnl Copyright (C) 2009-2017 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.
7 AC_DEFUN([gl_FUNC_PIPE2],
9 AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
11 dnl Persuade glibc <unistd.h> to declare pipe2().
12 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
14 AC_CHECK_FUNCS_ONCE([pipe2])
15 if test $ac_cv_func_pipe2 != yes; then