Commit | Line | Data |
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9157d901 | 1 | # include_next.m4 serial 15 |
61cd9dc9 | 2 | dnl Copyright (C) 2006-2010 Free Software Foundation, Inc. |
103dc4d4 LC |
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. | |
6 | ||
7 | dnl From Paul Eggert and Derek Price. | |
8 | ||
e65fc94b LC |
9 | dnl Sets INCLUDE_NEXT and PRAGMA_SYSTEM_HEADER. |
10 | dnl | |
11 | dnl INCLUDE_NEXT expands to 'include_next' if the compiler supports it, or to | |
12 | dnl 'include' otherwise. | |
13 | dnl | |
aa7a939c LC |
14 | dnl INCLUDE_NEXT_AS_FIRST_DIRECTIVE expands to 'include_next' if the compiler |
15 | dnl supports it in the special case that it is the first include directive in | |
16 | dnl the given file, or to 'include' otherwise. | |
17 | dnl | |
e65fc94b LC |
18 | dnl PRAGMA_SYSTEM_HEADER can be used in files that contain #include_next, |
19 | dnl so as to avoid GCC warnings when the gcc option -pedantic is used. | |
20 | dnl '#pragma GCC system_header' has the same effect as if the file was found | |
21 | dnl through the include search path specified with '-isystem' options (as | |
22 | dnl opposed to the search path specified with '-I' options). Namely, gcc | |
23 | dnl does not warn about some things, and on some systems (Solaris and Interix) | |
24 | dnl __STDC__ evaluates to 0 instead of to 1. The latter is an undesired side | |
25 | dnl effect; we are therefore careful to use 'defined __STDC__' or '1' instead | |
26 | dnl of plain '__STDC__'. | |
27 | ||
103dc4d4 LC |
28 | AC_DEFUN([gl_INCLUDE_NEXT], |
29 | [ | |
30 | AC_LANG_PREPROC_REQUIRE() | |
31 | AC_CACHE_CHECK([whether the preprocessor supports include_next], | |
32 | [gl_cv_have_include_next], | |
aa7a939c LC |
33 | [rm -rf conftestd1a conftestd1b conftestd2 |
34 | mkdir conftestd1a conftestd1b conftestd2 | |
f240aacb LC |
35 | dnl IBM C 9.0, 10.1 (original versions, prior to the 2009-01 updates) on |
36 | dnl AIX 6.1 support include_next when used as first preprocessor directive | |
37 | dnl in a file, but not when preceded by another include directive. Check | |
38 | dnl for this bug by including <stdio.h>. | |
39 | dnl Additionally, with this same compiler, include_next is a no-op when | |
40 | dnl used in a header file that was included by specifying its absolute | |
41 | dnl file name. Despite these two bugs, include_next is used in the | |
42 | dnl compiler's <math.h>. By virtue of the second bug, we need to use | |
43 | dnl include_next as well in this case. | |
aa7a939c LC |
44 | cat <<EOF > conftestd1a/conftest.h |
45 | #define DEFINED_IN_CONFTESTD1 | |
46 | #include_next <conftest.h> | |
47 | #ifdef DEFINED_IN_CONFTESTD2 | |
48 | int foo; | |
49 | #else | |
50 | #error "include_next doesn't work" | |
51 | #endif | |
52 | EOF | |
53 | cat <<EOF > conftestd1b/conftest.h | |
103dc4d4 | 54 | #define DEFINED_IN_CONFTESTD1 |
aa7a939c | 55 | #include <stdio.h> |
103dc4d4 LC |
56 | #include_next <conftest.h> |
57 | #ifdef DEFINED_IN_CONFTESTD2 | |
58 | int foo; | |
59 | #else | |
60 | #error "include_next doesn't work" | |
61 | #endif | |
62 | EOF | |
63 | cat <<EOF > conftestd2/conftest.h | |
64 | #ifndef DEFINED_IN_CONFTESTD1 | |
65 | #error "include_next test doesn't work" | |
66 | #endif | |
67 | #define DEFINED_IN_CONFTESTD2 | |
68 | EOF | |
aa7a939c LC |
69 | gl_save_CPPFLAGS="$CPPFLAGS" |
70 | CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1b -Iconftestd2" | |
9157d901 LC |
71 | dnl We intentionally avoid using AC_LANG_SOURCE here. |
72 | AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], | |
103dc4d4 | 73 | [gl_cv_have_include_next=yes], |
aa7a939c | 74 | [CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2" |
9157d901 | 75 | AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], |
aa7a939c LC |
76 | [gl_cv_have_include_next=buggy], |
77 | [gl_cv_have_include_next=no]) | |
78 | ]) | |
79 | CPPFLAGS="$gl_save_CPPFLAGS" | |
80 | rm -rf conftestd1a conftestd1b conftestd2 | |
103dc4d4 | 81 | ]) |
e65fc94b | 82 | PRAGMA_SYSTEM_HEADER= |
103dc4d4 | 83 | if test $gl_cv_have_include_next = yes; then |
103dc4d4 | 84 | INCLUDE_NEXT=include_next |
aa7a939c | 85 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next |
e65fc94b LC |
86 | if test -n "$GCC"; then |
87 | PRAGMA_SYSTEM_HEADER='#pragma GCC system_header' | |
88 | fi | |
103dc4d4 | 89 | else |
aa7a939c LC |
90 | if test $gl_cv_have_include_next = buggy; then |
91 | INCLUDE_NEXT=include | |
92 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next | |
93 | else | |
94 | INCLUDE_NEXT=include | |
95 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include | |
96 | fi | |
103dc4d4 LC |
97 | fi |
98 | AC_SUBST([INCLUDE_NEXT]) | |
aa7a939c | 99 | AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE]) |
e65fc94b | 100 | AC_SUBST([PRAGMA_SYSTEM_HEADER]) |
103dc4d4 LC |
101 | ]) |
102 | ||
103 | # gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...) | |
104 | # ------------------------------------------ | |
105 | # For each arg foo.h, if #include_next works, define NEXT_FOO_H to be | |
106 | # '<foo.h>'; otherwise define it to be | |
107 | # '"///usr/include/foo.h"', or whatever other absolute file name is suitable. | |
d9a9e182 AW |
108 | # Also, if #include_next works as first preprocessing directive in a file, |
109 | # define NEXT_AS_FIRST_DIRECTIVE_FOO_H to be '<foo.h>'; otherwise define it to | |
110 | # be | |
111 | # '"///usr/include/foo.h"', or whatever other absolute file name is suitable. | |
103dc4d4 | 112 | # That way, a header file with the following line: |
1cd4fffc | 113 | # #@INCLUDE_NEXT@ @NEXT_FOO_H@ |
d9a9e182 | 114 | # or |
1cd4fffc | 115 | # #@INCLUDE_NEXT_AS_FIRST_DIRECTIVE@ @NEXT_AS_FIRST_DIRECTIVE_FOO_H@ |
103dc4d4 | 116 | # behaves (after sed substitution) as if it contained |
1cd4fffc | 117 | # #include_next <foo.h> |
103dc4d4 LC |
118 | # even if the compiler does not support include_next. |
119 | # The three "///" are to pacify Sun C 5.8, which otherwise would say | |
120 | # "warning: #include of /usr/include/... may be non-portable". | |
121 | # Use `""', not `<>', so that the /// cannot be confused with a C99 comment. | |
122 | # Note: This macro assumes that the header file is not empty after | |
123 | # preprocessing, i.e. it does not only define preprocessor macros but also | |
124 | # provides some type/enum definitions or function/variable declarations. | |
125 | AC_DEFUN([gl_CHECK_NEXT_HEADERS], | |
126 | [ | |
127 | AC_REQUIRE([gl_INCLUDE_NEXT]) | |
aa7a939c | 128 | AC_REQUIRE([AC_CANONICAL_HOST]) |
103dc4d4 LC |
129 | AC_CHECK_HEADERS_ONCE([$1]) |
130 | ||
131 | m4_foreach_w([gl_HEADER_NAME], [$1], | |
132 | [AS_VAR_PUSHDEF([gl_next_header], | |
1cd4fffc | 133 | [gl_cv_next_]m4_defn([gl_HEADER_NAME])) |
103dc4d4 LC |
134 | if test $gl_cv_have_include_next = yes; then |
135 | AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>']) | |
136 | else | |
137 | AC_CACHE_CHECK( | |
1cd4fffc LC |
138 | [absolute name of <]m4_defn([gl_HEADER_NAME])[>], |
139 | m4_defn([gl_next_header]), | |
140 | [AS_VAR_PUSHDEF([gl_header_exists], | |
141 | [ac_cv_header_]m4_defn([gl_HEADER_NAME])) | |
142 | if test AS_VAR_GET(gl_header_exists) = yes; then | |
143 | AC_LANG_CONFTEST( | |
144 | [AC_LANG_SOURCE( | |
145 | [[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]] | |
146 | )]) | |
147 | dnl AIX "xlc -E" and "cc -E" omit #line directives for header files | |
148 | dnl that contain only a #include of other header files and no | |
149 | dnl non-comment tokens of their own. This leads to a failure to | |
150 | dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h> | |
151 | dnl and others. The workaround is to force preservation of comments | |
152 | dnl through option -C. This ensures all necessary #line directives | |
153 | dnl are present. GCC supports option -C as well. | |
154 | case "$host_os" in | |
155 | aix*) gl_absname_cpp="$ac_cpp -C" ;; | |
156 | *) gl_absname_cpp="$ac_cpp" ;; | |
157 | esac | |
158 | dnl eval is necessary to expand gl_absname_cpp. | |
159 | dnl Ultrix and Pyramid sh refuse to redirect output of eval, | |
160 | dnl so use subshell. | |
161 | AS_VAR_SET([gl_next_header], | |
162 | ['"'`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD | | |
163 | sed -n '\#/]m4_defn([gl_HEADER_NAME])[#{ | |
164 | s#.*"\(.*/]m4_defn([gl_HEADER_NAME])[\)".*#\1# | |
165 | s#^/[^/]#//&# | |
166 | p | |
167 | q | |
168 | }'`'"']) | |
169 | else | |
170 | AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>']) | |
171 | fi | |
172 | AS_VAR_POPDEF([gl_header_exists])]) | |
103dc4d4 LC |
173 | fi |
174 | AC_SUBST( | |
d9a9e182 | 175 | AS_TR_CPP([NEXT_]m4_defn([gl_HEADER_NAME])), |
103dc4d4 | 176 | [AS_VAR_GET([gl_next_header])]) |
d9a9e182 AW |
177 | if test $gl_cv_have_include_next = yes || test $gl_cv_have_include_next = buggy; then |
178 | # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include_next' | |
179 | gl_next_as_first_directive='<'gl_HEADER_NAME'>' | |
180 | else | |
181 | # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include' | |
182 | gl_next_as_first_directive=AS_VAR_GET([gl_next_header]) | |
183 | fi | |
184 | AC_SUBST( | |
185 | AS_TR_CPP([NEXT_AS_FIRST_DIRECTIVE_]m4_defn([gl_HEADER_NAME])), | |
186 | [$gl_next_as_first_directive]) | |
103dc4d4 LC |
187 | AS_VAR_POPDEF([gl_next_header])]) |
188 | ]) | |
9157d901 LC |
189 | |
190 | # Autoconf 2.68 added warnings for our use of AC_COMPILE_IFELSE; | |
191 | # this fallback is safe for all earlier autoconf versions. | |
192 | m4_define_default([AC_LANG_DEFINES_PROVIDED]) |