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-rw-r--r--m4/dup.m454
1 files changed, 54 insertions, 0 deletions
diff --git a/m4/dup.m4 b/m4/dup.m4
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+++ b/m4/dup.m4
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+# dup.m4 serial 7
+dnl Copyright (C) 2011-2022 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_DUP],
+[
+ AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ m4_ifdef([gl_MSVC_INVAL], [
+ AC_REQUIRE([gl_MSVC_INVAL])
+ if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
+ REPLACE_DUP=1
+ fi
+ ])
+ dnl Replace dup() for supporting the gnulib-defined fchdir() function,
+ dnl to keep fchdir's bookkeeping up-to-date.
+ m4_ifdef([gl_FUNC_FCHDIR], [
+ gl_TEST_FCHDIR
+ if test $HAVE_FCHDIR = 0; then
+ REPLACE_DUP=1
+ fi
+ ])
+ AC_CACHE_CHECK([whether dup works], [gl_cv_func_dup_works],
+ [AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM([[#include <unistd.h>
+ #include <fcntl.h>
+ #include <errno.h>
+ ]GL_MDA_DEFINES],
+ [[/* On OS/2 kLIBC, dup does not work on a directory fd. */
+ int fd = open (".", O_RDONLY);
+ return fd < 0 ? 1 : dup (fd) < 0 ? 2 : 0;
+ ]])
+ ],
+ [gl_cv_func_dup_works=yes],
+ [gl_cv_func_dup_works=no],
+ [case "$host_os" in
+ # Guess no on native Windows.
+ mingw*) gl_cv_func_dup_works="guessing no" ;;
+ *) gl_cv_func_dup_works="guessing yes" ;;
+ esac
+ ])
+ ])
+ case "$gl_cv_func_dup_works" in
+ *yes) ;;
+ *)
+ REPLACE_DUP=1
+ ;;
+ esac
+])
+
+# Prerequisites of lib/dup.c.
+AC_DEFUN([gl_PREREQ_DUP], [:])