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87 lines
2.6 KiB
Plaintext
87 lines
2.6 KiB
Plaintext
# serial 26 -*- Autoconf -*-
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dnl Find out how to get the file descriptor associated with an open DIR*.
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# Copyright (C) 2001-2006, 2008-2021 Free Software Foundation, Inc.
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# This file is free software; the Free Software Foundation
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# gives unlimited permission to copy and/or distribute it,
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# with or without modifications, as long as this notice is preserved.
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dnl From Jim Meyering
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AC_DEFUN([gl_FUNC_DIRFD],
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[
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AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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dnl Persuade glibc <dirent.h> to declare dirfd().
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AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
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AC_CHECK_FUNCS([dirfd])
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AC_CHECK_DECLS([dirfd], , ,
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[[#include <sys/types.h>
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#include <dirent.h>]])
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if test $ac_cv_have_decl_dirfd = no; then
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HAVE_DECL_DIRFD=0
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fi
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AC_CACHE_CHECK([whether dirfd is a macro],
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[gl_cv_func_dirfd_macro],
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[AC_EGREP_CPP([dirent_header_defines_dirfd], [
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#include <sys/types.h>
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#include <dirent.h>
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#ifdef dirfd
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dirent_header_defines_dirfd
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#endif],
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[gl_cv_func_dirfd_macro=yes],
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[gl_cv_func_dirfd_macro=no])])
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# Use the replacement if we have no function or macro with that name,
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# or if OS/2 kLIBC whose dirfd() does not work.
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# Replace only if the system declares dirfd already.
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case $ac_cv_func_dirfd,$gl_cv_func_dirfd_macro,$host_os,$ac_cv_have_decl_dirfd in
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no,no,*,yes | *,*,os2*,yes)
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REPLACE_DIRFD=1
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AC_DEFINE([REPLACE_DIRFD], [1],
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[Define to 1 if gnulib's dirfd() replacement is used.]);;
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esac
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])
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dnl Prerequisites of lib/dirfd.c.
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AC_DEFUN([gl_PREREQ_DIRFD],
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[
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AC_CACHE_CHECK([how to get the file descriptor associated with an open DIR*],
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[gl_cv_sys_dir_fd_member_name],
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[
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dirfd_save_CFLAGS=$CFLAGS
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for ac_expr in d_fd dd_fd; do
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CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
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AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
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#include <sys/types.h>
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#include <dirent.h>]],
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[[DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;]])],
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[dir_fd_found=yes]
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)
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CFLAGS=$dirfd_save_CFLAGS
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test "$dir_fd_found" = yes && break
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done
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test "$dir_fd_found" = yes || ac_expr=no_such_member
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gl_cv_sys_dir_fd_member_name=$ac_expr
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]
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)
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if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
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AC_DEFINE_UNQUOTED([DIR_FD_MEMBER_NAME],
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[$gl_cv_sys_dir_fd_member_name],
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[the name of the file descriptor member of DIR])
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fi
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AH_VERBATIM([DIR_TO_FD],
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[#ifdef DIR_FD_MEMBER_NAME
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# define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
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#else
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# define DIR_TO_FD(Dir_p) -1
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#endif
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])
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])
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