Commit | Line | Data |
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770d76d7 | 1 | # include_next.m4 serial 23 |
49e4877c | 2 | dnl Copyright (C) 2006-2016 Free Software Foundation, Inc. |
f6ea5628 DJ |
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 | ||
f434ba03 PA |
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 | |
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 | |
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__'. | |
770d76d7 PA |
27 | dnl |
28 | dnl PRAGMA_COLUMNS can be used in files that override system header files, so | |
29 | dnl as to avoid compilation errors on HP NonStop systems when the gnulib file | |
30 | dnl is included by a system header file that does a "#pragma COLUMNS 80" (which | |
31 | dnl has the effect of truncating the lines of that file and all files that it | |
32 | dnl includes to 80 columns) and the gnulib file has lines longer than 80 | |
33 | dnl columns. | |
f434ba03 | 34 | |
f6ea5628 DJ |
35 | AC_DEFUN([gl_INCLUDE_NEXT], |
36 | [ | |
37 | AC_LANG_PREPROC_REQUIRE() | |
38 | AC_CACHE_CHECK([whether the preprocessor supports include_next], | |
39 | [gl_cv_have_include_next], | |
f434ba03 PA |
40 | [rm -rf conftestd1a conftestd1b conftestd2 |
41 | mkdir conftestd1a conftestd1b conftestd2 | |
42 | dnl IBM C 9.0, 10.1 (original versions, prior to the 2009-01 updates) on | |
43 | dnl AIX 6.1 support include_next when used as first preprocessor directive | |
44 | dnl in a file, but not when preceded by another include directive. Check | |
45 | dnl for this bug by including <stdio.h>. | |
46 | dnl Additionally, with this same compiler, include_next is a no-op when | |
47 | dnl used in a header file that was included by specifying its absolute | |
48 | dnl file name. Despite these two bugs, include_next is used in the | |
49 | dnl compiler's <math.h>. By virtue of the second bug, we need to use | |
50 | dnl include_next as well in this case. | |
51 | cat <<EOF > conftestd1a/conftest.h | |
f6ea5628 DJ |
52 | #define DEFINED_IN_CONFTESTD1 |
53 | #include_next <conftest.h> | |
54 | #ifdef DEFINED_IN_CONFTESTD2 | |
55 | int foo; | |
56 | #else | |
57 | #error "include_next doesn't work" | |
58 | #endif | |
f434ba03 PA |
59 | EOF |
60 | cat <<EOF > conftestd1b/conftest.h | |
61 | #define DEFINED_IN_CONFTESTD1 | |
62 | #include <stdio.h> | |
63 | #include_next <conftest.h> | |
64 | #ifdef DEFINED_IN_CONFTESTD2 | |
65 | int foo; | |
66 | #else | |
67 | #error "include_next doesn't work" | |
68 | #endif | |
f6ea5628 DJ |
69 | EOF |
70 | cat <<EOF > conftestd2/conftest.h | |
71 | #ifndef DEFINED_IN_CONFTESTD1 | |
72 | #error "include_next test doesn't work" | |
73 | #endif | |
74 | #define DEFINED_IN_CONFTESTD2 | |
75 | EOF | |
f434ba03 PA |
76 | gl_save_CPPFLAGS="$CPPFLAGS" |
77 | CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1b -Iconftestd2" | |
770d76d7 PA |
78 | dnl We intentionally avoid using AC_LANG_SOURCE here. |
79 | AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], | |
f6ea5628 | 80 | [gl_cv_have_include_next=yes], |
f434ba03 | 81 | [CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2" |
770d76d7 | 82 | AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], |
f434ba03 PA |
83 | [gl_cv_have_include_next=buggy], |
84 | [gl_cv_have_include_next=no]) | |
85 | ]) | |
86 | CPPFLAGS="$gl_save_CPPFLAGS" | |
87 | rm -rf conftestd1a conftestd1b conftestd2 | |
f6ea5628 | 88 | ]) |
f434ba03 | 89 | PRAGMA_SYSTEM_HEADER= |
f6ea5628 | 90 | if test $gl_cv_have_include_next = yes; then |
f6ea5628 | 91 | INCLUDE_NEXT=include_next |
f434ba03 PA |
92 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next |
93 | if test -n "$GCC"; then | |
94 | PRAGMA_SYSTEM_HEADER='#pragma GCC system_header' | |
95 | fi | |
f6ea5628 | 96 | else |
f434ba03 PA |
97 | if test $gl_cv_have_include_next = buggy; then |
98 | INCLUDE_NEXT=include | |
99 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next | |
100 | else | |
101 | INCLUDE_NEXT=include | |
102 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include | |
103 | fi | |
f6ea5628 DJ |
104 | fi |
105 | AC_SUBST([INCLUDE_NEXT]) | |
f434ba03 PA |
106 | AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE]) |
107 | AC_SUBST([PRAGMA_SYSTEM_HEADER]) | |
770d76d7 PA |
108 | AC_CACHE_CHECK([whether system header files limit the line length], |
109 | [gl_cv_pragma_columns], | |
110 | [dnl HP NonStop systems, which define __TANDEM, have this misfeature. | |
111 | AC_EGREP_CPP([choke me], | |
112 | [ | |
113 | #ifdef __TANDEM | |
114 | choke me | |
115 | #endif | |
116 | ], | |
117 | [gl_cv_pragma_columns=yes], | |
118 | [gl_cv_pragma_columns=no]) | |
119 | ]) | |
120 | if test $gl_cv_pragma_columns = yes; then | |
121 | PRAGMA_COLUMNS="#pragma COLUMNS 10000" | |
122 | else | |
123 | PRAGMA_COLUMNS= | |
124 | fi | |
125 | AC_SUBST([PRAGMA_COLUMNS]) | |
f6ea5628 DJ |
126 | ]) |
127 | ||
128 | # gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...) | |
129 | # ------------------------------------------ | |
130 | # For each arg foo.h, if #include_next works, define NEXT_FOO_H to be | |
131 | # '<foo.h>'; otherwise define it to be | |
132 | # '"///usr/include/foo.h"', or whatever other absolute file name is suitable. | |
f434ba03 PA |
133 | # Also, if #include_next works as first preprocessing directive in a file, |
134 | # define NEXT_AS_FIRST_DIRECTIVE_FOO_H to be '<foo.h>'; otherwise define it to | |
135 | # be | |
136 | # '"///usr/include/foo.h"', or whatever other absolute file name is suitable. | |
f6ea5628 | 137 | # That way, a header file with the following line: |
f434ba03 PA |
138 | # #@INCLUDE_NEXT@ @NEXT_FOO_H@ |
139 | # or | |
140 | # #@INCLUDE_NEXT_AS_FIRST_DIRECTIVE@ @NEXT_AS_FIRST_DIRECTIVE_FOO_H@ | |
f6ea5628 | 141 | # behaves (after sed substitution) as if it contained |
f434ba03 | 142 | # #include_next <foo.h> |
f6ea5628 DJ |
143 | # even if the compiler does not support include_next. |
144 | # The three "///" are to pacify Sun C 5.8, which otherwise would say | |
145 | # "warning: #include of /usr/include/... may be non-portable". | |
770d76d7 | 146 | # Use '""', not '<>', so that the /// cannot be confused with a C99 comment. |
f434ba03 PA |
147 | # Note: This macro assumes that the header file is not empty after |
148 | # preprocessing, i.e. it does not only define preprocessor macros but also | |
149 | # provides some type/enum definitions or function/variable declarations. | |
770d76d7 PA |
150 | # |
151 | # This macro also checks whether each header exists, by invoking | |
152 | # AC_CHECK_HEADERS_ONCE or AC_CHECK_HEADERS on each argument. | |
f6ea5628 | 153 | AC_DEFUN([gl_CHECK_NEXT_HEADERS], |
770d76d7 PA |
154 | [ |
155 | gl_NEXT_HEADERS_INTERNAL([$1], [check]) | |
156 | ]) | |
157 | ||
158 | # gl_NEXT_HEADERS(HEADER1 HEADER2 ...) | |
159 | # ------------------------------------ | |
160 | # Like gl_CHECK_NEXT_HEADERS, except do not check whether the headers exist. | |
161 | # This is suitable for headers like <stddef.h> that are standardized by C89 | |
162 | # and therefore can be assumed to exist. | |
163 | AC_DEFUN([gl_NEXT_HEADERS], | |
164 | [ | |
165 | gl_NEXT_HEADERS_INTERNAL([$1], [assume]) | |
166 | ]) | |
167 | ||
168 | # The guts of gl_CHECK_NEXT_HEADERS and gl_NEXT_HEADERS. | |
169 | AC_DEFUN([gl_NEXT_HEADERS_INTERNAL], | |
f6ea5628 DJ |
170 | [ |
171 | AC_REQUIRE([gl_INCLUDE_NEXT]) | |
f434ba03 | 172 | AC_REQUIRE([AC_CANONICAL_HOST]) |
f6ea5628 | 173 | |
770d76d7 PA |
174 | m4_if([$2], [check], |
175 | [AC_CHECK_HEADERS_ONCE([$1]) | |
176 | ]) | |
177 | ||
178 | dnl FIXME: gl_next_header and gl_header_exists must be used unquoted | |
179 | dnl until we can assume autoconf 2.64 or newer. | |
f434ba03 | 180 | m4_foreach_w([gl_HEADER_NAME], [$1], |
f6ea5628 | 181 | [AS_VAR_PUSHDEF([gl_next_header], |
f434ba03 | 182 | [gl_cv_next_]m4_defn([gl_HEADER_NAME])) |
f6ea5628 | 183 | if test $gl_cv_have_include_next = yes; then |
770d76d7 | 184 | AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>']) |
f6ea5628 DJ |
185 | else |
186 | AC_CACHE_CHECK( | |
f434ba03 PA |
187 | [absolute name of <]m4_defn([gl_HEADER_NAME])[>], |
188 | m4_defn([gl_next_header]), | |
770d76d7 PA |
189 | [m4_if([$2], [check], |
190 | [AS_VAR_PUSHDEF([gl_header_exists], | |
191 | [ac_cv_header_]m4_defn([gl_HEADER_NAME])) | |
192 | if test AS_VAR_GET(gl_header_exists) = yes; then | |
193 | AS_VAR_POPDEF([gl_header_exists]) | |
194 | ]) | |
4a626d0a PA |
195 | gl_ABSOLUTE_HEADER_ONE(gl_HEADER_NAME) |
196 | AS_VAR_COPY([gl_header], [gl_cv_absolute_]AS_TR_SH(gl_HEADER_NAME)) | |
197 | AS_VAR_SET(gl_next_header, ['"'$gl_header'"']) | |
770d76d7 PA |
198 | m4_if([$2], [check], |
199 | [else | |
200 | AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>']) | |
201 | fi | |
202 | ]) | |
203 | ]) | |
f6ea5628 DJ |
204 | fi |
205 | AC_SUBST( | |
f434ba03 | 206 | AS_TR_CPP([NEXT_]m4_defn([gl_HEADER_NAME])), |
770d76d7 | 207 | [AS_VAR_GET(gl_next_header)]) |
f434ba03 PA |
208 | if test $gl_cv_have_include_next = yes || test $gl_cv_have_include_next = buggy; then |
209 | # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include_next' | |
210 | gl_next_as_first_directive='<'gl_HEADER_NAME'>' | |
211 | else | |
212 | # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include' | |
770d76d7 | 213 | gl_next_as_first_directive=AS_VAR_GET(gl_next_header) |
f434ba03 PA |
214 | fi |
215 | AC_SUBST( | |
216 | AS_TR_CPP([NEXT_AS_FIRST_DIRECTIVE_]m4_defn([gl_HEADER_NAME])), | |
217 | [$gl_next_as_first_directive]) | |
f6ea5628 DJ |
218 | AS_VAR_POPDEF([gl_next_header])]) |
219 | ]) | |
770d76d7 PA |
220 | |
221 | # Autoconf 2.68 added warnings for our use of AC_COMPILE_IFELSE; | |
222 | # this fallback is safe for all earlier autoconf versions. | |
223 | m4_define_default([AC_LANG_DEFINES_PROVIDED]) |