1# onceonly.m4 serial 9 2dnl Copyright (C) 2002-2003, 2005-2006, 2008-2015 Free Software Foundation, 3dnl Inc. 4dnl 5dnl This file is free software; you can redistribute it and/or modify 6dnl it under the terms of the GNU General Public License as published by 7dnl the Free Software Foundation; either version 3 of the License, or 8dnl (at your option) any later version. 9dnl 10dnl This file is distributed in the hope that it will be useful, 11dnl but WITHOUT ANY WARRANTY; without even the implied warranty of 12dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13dnl GNU General Public License for more details. 14dnl 15dnl You should have received a copy of the GNU General Public License 16dnl along with this file. If not, see <http://www.gnu.org/licenses/>. 17dnl 18dnl As a special exception to the GNU General Public License, 19dnl this file may be distributed as part of a program 20dnl that contains a configuration script generated by Autoconf, under 21dnl the same distribution terms as the rest of that program. 22 23dnl This file defines some "once only" variants of standard autoconf macros. 24dnl AC_CHECK_HEADERS_ONCE like AC_CHECK_HEADERS 25dnl AC_CHECK_FUNCS_ONCE like AC_CHECK_FUNCS 26dnl AC_CHECK_DECLS_ONCE like AC_CHECK_DECLS 27dnl AC_REQUIRE([AC_FUNC_STRCOLL]) like AC_FUNC_STRCOLL 28dnl The advantage is that the check for each of the headers/functions/decls 29dnl will be put only once into the 'configure' file. It keeps the size of 30dnl the 'configure' file down, and avoids redundant output when 'configure' 31dnl is run. 32dnl The drawback is that the checks cannot be conditionalized. If you write 33dnl if some_condition; then gl_CHECK_HEADERS(stdlib.h); fi 34dnl inside an AC_DEFUNed function, the gl_CHECK_HEADERS macro call expands to 35dnl empty, and the check will be inserted before the body of the AC_DEFUNed 36dnl function. 37 38dnl The original code implemented AC_CHECK_HEADERS_ONCE and AC_CHECK_FUNCS_ONCE 39dnl in terms of AC_DEFUN and AC_REQUIRE. This implementation uses diversions to 40dnl named sections DEFAULTS and INIT_PREPARE in order to check all requested 41dnl headers at once, thus reducing the size of 'configure'. It is known to work 42dnl with autoconf 2.57..2.62 at least . The size reduction is ca. 9%. 43 44dnl Autoconf version 2.59 plus gnulib is required; this file is not needed 45dnl with Autoconf 2.60 or greater. But note that autoconf's implementation of 46dnl AC_CHECK_DECLS_ONCE expects a comma-separated list of symbols as first 47dnl argument! 48AC_PREREQ([2.59]) 49 50# AC_CHECK_HEADERS_ONCE(HEADER1 HEADER2 ...) is a once-only variant of 51# AC_CHECK_HEADERS(HEADER1 HEADER2 ...). 52AC_DEFUN([AC_CHECK_HEADERS_ONCE], [ 53 : 54 m4_foreach_w([gl_HEADER_NAME], [$1], [ 55 AC_DEFUN([gl_CHECK_HEADER_]m4_quote(m4_translit(gl_HEADER_NAME, 56 [./-], [___])), [ 57 m4_divert_text([INIT_PREPARE], 58 [gl_header_list="$gl_header_list gl_HEADER_NAME"]) 59 gl_HEADERS_EXPANSION 60 AH_TEMPLATE(AS_TR_CPP([HAVE_]m4_defn([gl_HEADER_NAME])), 61 [Define to 1 if you have the <]m4_defn([gl_HEADER_NAME])[> header file.]) 62 ]) 63 AC_REQUIRE([gl_CHECK_HEADER_]m4_quote(m4_translit(gl_HEADER_NAME, 64 [./-], [___]))) 65 ]) 66]) 67m4_define([gl_HEADERS_EXPANSION], [ 68 m4_divert_text([DEFAULTS], [gl_header_list=]) 69 AC_CHECK_HEADERS([$gl_header_list]) 70 m4_define([gl_HEADERS_EXPANSION], []) 71]) 72 73# AC_CHECK_FUNCS_ONCE(FUNC1 FUNC2 ...) is a once-only variant of 74# AC_CHECK_FUNCS(FUNC1 FUNC2 ...). 75AC_DEFUN([AC_CHECK_FUNCS_ONCE], [ 76 : 77 m4_foreach_w([gl_FUNC_NAME], [$1], [ 78 AC_DEFUN([gl_CHECK_FUNC_]m4_defn([gl_FUNC_NAME]), [ 79 m4_divert_text([INIT_PREPARE], 80 [gl_func_list="$gl_func_list gl_FUNC_NAME"]) 81 gl_FUNCS_EXPANSION 82 AH_TEMPLATE(AS_TR_CPP([HAVE_]m4_defn([gl_FUNC_NAME])), 83 [Define to 1 if you have the ']m4_defn([gl_FUNC_NAME])[' function.]) 84 ]) 85 AC_REQUIRE([gl_CHECK_FUNC_]m4_defn([gl_FUNC_NAME])) 86 ]) 87]) 88m4_define([gl_FUNCS_EXPANSION], [ 89 m4_divert_text([DEFAULTS], [gl_func_list=]) 90 AC_CHECK_FUNCS([$gl_func_list]) 91 m4_define([gl_FUNCS_EXPANSION], []) 92]) 93 94# AC_CHECK_DECLS_ONCE(DECL1 DECL2 ...) is a once-only variant of 95# AC_CHECK_DECLS(DECL1, DECL2, ...). 96AC_DEFUN([AC_CHECK_DECLS_ONCE], [ 97 : 98 m4_foreach_w([gl_DECL_NAME], [$1], [ 99 AC_DEFUN([gl_CHECK_DECL_]m4_defn([gl_DECL_NAME]), [ 100 AC_CHECK_DECLS(m4_defn([gl_DECL_NAME])) 101 ]) 102 AC_REQUIRE([gl_CHECK_DECL_]m4_defn([gl_DECL_NAME])) 103 ]) 104]) 105