1# absolute-header.m4 serial 17 2dnl Copyright (C) 2006-2021 Free Software Foundation, Inc. 3dnl This file is free software; the Free Software Foundation 4dnl gives unlimited permission to copy and/or distribute it, 5dnl with or without modifications, as long as this notice is preserved. 6 7dnl From Derek Price. 8 9# gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...) 10# --------------------------------------- 11# Find the absolute name of a header file, testing first if the header exists. 12# If the header were sys/inttypes.h, this macro would define 13# ABSOLUTE_SYS_INTTYPES_H to the '""' quoted absolute name of sys/inttypes.h 14# in config.h 15# (e.g. '#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"'). 16# The three "///" are to pacify Sun C 5.8, which otherwise would say 17# "warning: #include of /usr/include/... may be non-portable". 18# Use '""', not '<>', so that the /// cannot be confused with a C99 comment. 19# Note: This macro assumes that the header file is not empty after 20# preprocessing, i.e. it does not only define preprocessor macros but also 21# provides some type/enum definitions or function/variable declarations. 22AC_DEFUN([gl_ABSOLUTE_HEADER], 23[AC_REQUIRE([AC_CANONICAL_HOST]) 24AC_LANG_PREPROC_REQUIRE()dnl 25m4_foreach_w([gl_HEADER_NAME], [$1], 26 [AS_VAR_PUSHDEF([gl_absolute_header], 27 [gl_cv_absolute_]m4_defn([gl_HEADER_NAME]))dnl 28 AC_CACHE_CHECK([absolute name of <]m4_defn([gl_HEADER_NAME])[>], 29 [gl_absolute_header], 30 [AS_VAR_PUSHDEF([ac_header_exists], 31 [ac_cv_header_]m4_defn([gl_HEADER_NAME]))dnl 32 AC_CHECK_HEADERS_ONCE(m4_defn([gl_HEADER_NAME]))dnl 33 if test AS_VAR_GET([ac_header_exists]) = yes; then 34 gl_ABSOLUTE_HEADER_ONE(m4_defn([gl_HEADER_NAME])) 35 fi 36 AS_VAR_POPDEF([ac_header_exists])dnl 37 ])dnl 38 AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_defn([gl_HEADER_NAME])), 39 ["AS_VAR_GET([gl_absolute_header])"], 40 [Define this to an absolute name of <]m4_defn([gl_HEADER_NAME])[>.]) 41 AS_VAR_POPDEF([gl_absolute_header])dnl 42])dnl 43])# gl_ABSOLUTE_HEADER 44 45# gl_ABSOLUTE_HEADER_ONE(HEADER) 46# ------------------------------ 47# Like gl_ABSOLUTE_HEADER, except that: 48# - it assumes that the header exists, 49# - it uses the current CPPFLAGS, 50# - it does not cache the result, 51# - it is silent. 52AC_DEFUN([gl_ABSOLUTE_HEADER_ONE], 53[ 54 AC_REQUIRE([AC_CANONICAL_HOST]) 55 AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote([$1])[[>]])]) 56 dnl AIX "xlc -E" and "cc -E" omit #line directives for header files 57 dnl that contain only a #include of other header files and no 58 dnl non-comment tokens of their own. This leads to a failure to 59 dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h> 60 dnl and others. The workaround is to force preservation of comments 61 dnl through option -C. This ensures all necessary #line directives 62 dnl are present. GCC supports option -C as well. 63 case "$host_os" in 64 aix*) gl_absname_cpp="$ac_cpp -C" ;; 65 *) gl_absname_cpp="$ac_cpp" ;; 66 esac 67changequote(,) 68 case "$host_os" in 69 mingw*) 70 dnl For the sake of native Windows compilers (excluding gcc), 71 dnl treat backslash as a directory separator, like /. 72 dnl Actually, these compilers use a double-backslash as 73 dnl directory separator, inside the 74 dnl # line "filename" 75 dnl directives. 76 gl_dirsep_regex='[/\\]' 77 ;; 78 *) 79 gl_dirsep_regex='\/' 80 ;; 81 esac 82 dnl A sed expression that turns a string into a basic regular 83 dnl expression, for use within "/.../". 84 gl_make_literal_regex_sed='s,[]$^\\.*/[],\\&,g' 85 gl_header_literal_regex=`echo '$1' \ 86 | sed -e "$gl_make_literal_regex_sed"` 87 gl_absolute_header_sed="/${gl_dirsep_regex}${gl_header_literal_regex}/"'{ 88 s/.*"\(.*'"${gl_dirsep_regex}${gl_header_literal_regex}"'\)".*/\1/ 89 s|^/[^/]|//&| 90 p 91 q 92 }' 93changequote([,]) 94 dnl eval is necessary to expand gl_absname_cpp. 95 dnl Ultrix and Pyramid sh refuse to redirect output of eval, 96 dnl so use subshell. 97 AS_VAR_SET([gl_cv_absolute_]AS_TR_SH([[$1]]), 98[`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD | 99 sed -n "$gl_absolute_header_sed"`]) 100]) 101