Commit | Line | Data |
---|---|---|
aa7a939c | 1 | # include_next.m4 serial 10 |
103dc4d4 LC |
2 | dnl Copyright (C) 2006-2008 Free Software Foundation, Inc. |
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 | |
35 | dnl The include of <stdio.h> is because IBM C 9.0 on AIX 6.1 supports | |
36 | dnl include_next when used as first preprocessor directive in a file, | |
37 | dnl but not when preceded by another include directive. Additionally, | |
38 | dnl with this same compiler, include_next is a no-op when used in a | |
39 | dnl header file that was included by specifying its absolute file name. | |
40 | dnl Despite these two bugs, include_next is used in the compiler's | |
41 | dnl <math.h>. By virtue of the second bug, we need to use include_next | |
42 | dnl as well in this case. | |
43 | cat <<EOF > conftestd1a/conftest.h | |
44 | #define DEFINED_IN_CONFTESTD1 | |
45 | #include_next <conftest.h> | |
46 | #ifdef DEFINED_IN_CONFTESTD2 | |
47 | int foo; | |
48 | #else | |
49 | #error "include_next doesn't work" | |
50 | #endif | |
51 | EOF | |
52 | cat <<EOF > conftestd1b/conftest.h | |
103dc4d4 | 53 | #define DEFINED_IN_CONFTESTD1 |
aa7a939c | 54 | #include <stdio.h> |
103dc4d4 LC |
55 | #include_next <conftest.h> |
56 | #ifdef DEFINED_IN_CONFTESTD2 | |
57 | int foo; | |
58 | #else | |
59 | #error "include_next doesn't work" | |
60 | #endif | |
61 | EOF | |
62 | cat <<EOF > conftestd2/conftest.h | |
63 | #ifndef DEFINED_IN_CONFTESTD1 | |
64 | #error "include_next test doesn't work" | |
65 | #endif | |
66 | #define DEFINED_IN_CONFTESTD2 | |
67 | EOF | |
aa7a939c LC |
68 | gl_save_CPPFLAGS="$CPPFLAGS" |
69 | CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1b -Iconftestd2" | |
103dc4d4 LC |
70 | AC_COMPILE_IFELSE([#include <conftest.h>], |
71 | [gl_cv_have_include_next=yes], | |
aa7a939c LC |
72 | [CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2" |
73 | AC_COMPILE_IFELSE([#include <conftest.h>], | |
74 | [gl_cv_have_include_next=buggy], | |
75 | [gl_cv_have_include_next=no]) | |
76 | ]) | |
77 | CPPFLAGS="$gl_save_CPPFLAGS" | |
78 | rm -rf conftestd1a conftestd1b conftestd2 | |
103dc4d4 | 79 | ]) |
e65fc94b | 80 | PRAGMA_SYSTEM_HEADER= |
103dc4d4 | 81 | if test $gl_cv_have_include_next = yes; then |
103dc4d4 | 82 | INCLUDE_NEXT=include_next |
aa7a939c | 83 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next |
e65fc94b LC |
84 | if test -n "$GCC"; then |
85 | PRAGMA_SYSTEM_HEADER='#pragma GCC system_header' | |
86 | fi | |
103dc4d4 | 87 | else |
aa7a939c LC |
88 | if test $gl_cv_have_include_next = buggy; then |
89 | INCLUDE_NEXT=include | |
90 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next | |
91 | else | |
92 | INCLUDE_NEXT=include | |
93 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include | |
94 | fi | |
103dc4d4 LC |
95 | fi |
96 | AC_SUBST([INCLUDE_NEXT]) | |
aa7a939c | 97 | AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE]) |
e65fc94b | 98 | AC_SUBST([PRAGMA_SYSTEM_HEADER]) |
103dc4d4 LC |
99 | ]) |
100 | ||
101 | # gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...) | |
102 | # ------------------------------------------ | |
103 | # For each arg foo.h, if #include_next works, define NEXT_FOO_H to be | |
104 | # '<foo.h>'; otherwise define it to be | |
105 | # '"///usr/include/foo.h"', or whatever other absolute file name is suitable. | |
106 | # That way, a header file with the following line: | |
107 | # #@INCLUDE_NEXT@ @NEXT_FOO_H@ | |
108 | # behaves (after sed substitution) as if it contained | |
109 | # #include_next <foo.h> | |
110 | # even if the compiler does not support include_next. | |
111 | # The three "///" are to pacify Sun C 5.8, which otherwise would say | |
112 | # "warning: #include of /usr/include/... may be non-portable". | |
113 | # Use `""', not `<>', so that the /// cannot be confused with a C99 comment. | |
114 | # Note: This macro assumes that the header file is not empty after | |
115 | # preprocessing, i.e. it does not only define preprocessor macros but also | |
116 | # provides some type/enum definitions or function/variable declarations. | |
117 | AC_DEFUN([gl_CHECK_NEXT_HEADERS], | |
118 | [ | |
119 | AC_REQUIRE([gl_INCLUDE_NEXT]) | |
aa7a939c | 120 | AC_REQUIRE([AC_CANONICAL_HOST]) |
103dc4d4 LC |
121 | AC_CHECK_HEADERS_ONCE([$1]) |
122 | ||
123 | m4_foreach_w([gl_HEADER_NAME], [$1], | |
124 | [AS_VAR_PUSHDEF([gl_next_header], | |
125 | [gl_cv_next_]m4_quote(m4_defn([gl_HEADER_NAME]))) | |
126 | if test $gl_cv_have_include_next = yes; then | |
127 | AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>']) | |
128 | else | |
129 | AC_CACHE_CHECK( | |
130 | [absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>], | |
131 | m4_quote(m4_defn([gl_next_header])), | |
132 | [AS_VAR_PUSHDEF([gl_header_exists], | |
133 | [ac_cv_header_]m4_quote(m4_defn([gl_HEADER_NAME]))) | |
134 | if test AS_VAR_GET(gl_header_exists) = yes; then | |
135 | AC_LANG_CONFTEST( | |
136 | [AC_LANG_SOURCE( | |
137 | [[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]] | |
138 | )]) | |
aa7a939c LC |
139 | dnl AIX "xlc -E" and "cc -E" omit #line directives for header files |
140 | dnl that contain only a #include of other header files and no | |
141 | dnl non-comment tokens of their own. This leads to a failure to | |
142 | dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h> | |
143 | dnl and others. The workaround is to force preservation of comments | |
144 | dnl through option -C. This ensures all necessary #line directives | |
145 | dnl are present. GCC supports option -C as well. | |
146 | case "$host_os" in | |
147 | aix*) gl_absname_cpp="$ac_cpp -C" ;; | |
148 | *) gl_absname_cpp="$ac_cpp" ;; | |
149 | esac | |
150 | dnl eval is necessary to expand gl_absname_cpp. | |
103dc4d4 LC |
151 | dnl Ultrix and Pyramid sh refuse to redirect output of eval, |
152 | dnl so use subshell. | |
153 | AS_VAR_SET([gl_next_header], | |
aa7a939c | 154 | ['"'`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD | |
103dc4d4 LC |
155 | sed -n '\#/]m4_quote(m4_defn([gl_HEADER_NAME]))[#{ |
156 | s#.*"\(.*/]m4_quote(m4_defn([gl_HEADER_NAME]))[\)".*#\1# | |
157 | s#^/[^/]#//&# | |
158 | p | |
159 | q | |
160 | }'`'"']) | |
161 | else | |
162 | AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>']) | |
163 | fi | |
164 | AS_VAR_POPDEF([gl_header_exists])]) | |
165 | fi | |
166 | AC_SUBST( | |
167 | AS_TR_CPP([NEXT_]m4_quote(m4_defn([gl_HEADER_NAME]))), | |
168 | [AS_VAR_GET([gl_next_header])]) | |
169 | AS_VAR_POPDEF([gl_next_header])]) | |
170 | ]) |