Commit | Line | Data |
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c0c3707f | 1 | # include_next.m4 serial 24 |
5df4cba6 | 2 | dnl Copyright (C) 2006-2020 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 | ||
c0c3707f CB |
9 | dnl Sets INCLUDE_NEXT, INCLUDE_NEXT_AS_FIRST_DIRECTIVE, PRAGMA_SYSTEM_HEADER, |
10 | dnl and PRAGMA_COLUMNS. | |
f434ba03 PA |
11 | dnl |
12 | dnl INCLUDE_NEXT expands to 'include_next' if the compiler supports it, or to | |
13 | dnl 'include' otherwise. | |
14 | dnl | |
15 | dnl INCLUDE_NEXT_AS_FIRST_DIRECTIVE expands to 'include_next' if the compiler | |
16 | dnl supports it in the special case that it is the first include directive in | |
17 | dnl the given file, or to 'include' otherwise. | |
18 | dnl | |
19 | dnl PRAGMA_SYSTEM_HEADER can be used in files that contain #include_next, | |
20 | dnl so as to avoid GCC warnings when the gcc option -pedantic is used. | |
21 | dnl '#pragma GCC system_header' has the same effect as if the file was found | |
22 | dnl through the include search path specified with '-isystem' options (as | |
23 | dnl opposed to the search path specified with '-I' options). Namely, gcc | |
24 | dnl does not warn about some things, and on some systems (Solaris and Interix) | |
25 | dnl __STDC__ evaluates to 0 instead of to 1. The latter is an undesired side | |
26 | dnl effect; we are therefore careful to use 'defined __STDC__' or '1' instead | |
27 | dnl of plain '__STDC__'. | |
770d76d7 PA |
28 | dnl |
29 | dnl PRAGMA_COLUMNS can be used in files that override system header files, so | |
30 | dnl as to avoid compilation errors on HP NonStop systems when the gnulib file | |
31 | dnl is included by a system header file that does a "#pragma COLUMNS 80" (which | |
32 | dnl has the effect of truncating the lines of that file and all files that it | |
33 | dnl includes to 80 columns) and the gnulib file has lines longer than 80 | |
34 | dnl columns. | |
f434ba03 | 35 | |
f6ea5628 DJ |
36 | AC_DEFUN([gl_INCLUDE_NEXT], |
37 | [ | |
38 | AC_LANG_PREPROC_REQUIRE() | |
39 | AC_CACHE_CHECK([whether the preprocessor supports include_next], | |
40 | [gl_cv_have_include_next], | |
f434ba03 PA |
41 | [rm -rf conftestd1a conftestd1b conftestd2 |
42 | mkdir conftestd1a conftestd1b conftestd2 | |
43 | dnl IBM C 9.0, 10.1 (original versions, prior to the 2009-01 updates) on | |
44 | dnl AIX 6.1 support include_next when used as first preprocessor directive | |
45 | dnl in a file, but not when preceded by another include directive. Check | |
46 | dnl for this bug by including <stdio.h>. | |
47 | dnl Additionally, with this same compiler, include_next is a no-op when | |
48 | dnl used in a header file that was included by specifying its absolute | |
49 | dnl file name. Despite these two bugs, include_next is used in the | |
50 | dnl compiler's <math.h>. By virtue of the second bug, we need to use | |
51 | dnl include_next as well in this case. | |
52 | cat <<EOF > conftestd1a/conftest.h | |
f6ea5628 DJ |
53 | #define DEFINED_IN_CONFTESTD1 |
54 | #include_next <conftest.h> | |
55 | #ifdef DEFINED_IN_CONFTESTD2 | |
56 | int foo; | |
57 | #else | |
58 | #error "include_next doesn't work" | |
59 | #endif | |
f434ba03 PA |
60 | EOF |
61 | cat <<EOF > conftestd1b/conftest.h | |
62 | #define DEFINED_IN_CONFTESTD1 | |
63 | #include <stdio.h> | |
64 | #include_next <conftest.h> | |
65 | #ifdef DEFINED_IN_CONFTESTD2 | |
66 | int foo; | |
67 | #else | |
68 | #error "include_next doesn't work" | |
69 | #endif | |
f6ea5628 DJ |
70 | EOF |
71 | cat <<EOF > conftestd2/conftest.h | |
72 | #ifndef DEFINED_IN_CONFTESTD1 | |
73 | #error "include_next test doesn't work" | |
74 | #endif | |
75 | #define DEFINED_IN_CONFTESTD2 | |
76 | EOF | |
f434ba03 PA |
77 | gl_save_CPPFLAGS="$CPPFLAGS" |
78 | CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1b -Iconftestd2" | |
770d76d7 PA |
79 | dnl We intentionally avoid using AC_LANG_SOURCE here. |
80 | AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], | |
f6ea5628 | 81 | [gl_cv_have_include_next=yes], |
f434ba03 | 82 | [CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2" |
770d76d7 | 83 | AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], |
f434ba03 PA |
84 | [gl_cv_have_include_next=buggy], |
85 | [gl_cv_have_include_next=no]) | |
86 | ]) | |
87 | CPPFLAGS="$gl_save_CPPFLAGS" | |
88 | rm -rf conftestd1a conftestd1b conftestd2 | |
f6ea5628 | 89 | ]) |
f434ba03 | 90 | PRAGMA_SYSTEM_HEADER= |
f6ea5628 | 91 | if test $gl_cv_have_include_next = yes; then |
f6ea5628 | 92 | INCLUDE_NEXT=include_next |
f434ba03 PA |
93 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next |
94 | if test -n "$GCC"; then | |
95 | PRAGMA_SYSTEM_HEADER='#pragma GCC system_header' | |
96 | fi | |
f6ea5628 | 97 | else |
f434ba03 PA |
98 | if test $gl_cv_have_include_next = buggy; then |
99 | INCLUDE_NEXT=include | |
100 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next | |
101 | else | |
102 | INCLUDE_NEXT=include | |
103 | INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include | |
104 | fi | |
f6ea5628 DJ |
105 | fi |
106 | AC_SUBST([INCLUDE_NEXT]) | |
f434ba03 PA |
107 | AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE]) |
108 | AC_SUBST([PRAGMA_SYSTEM_HEADER]) | |
770d76d7 PA |
109 | AC_CACHE_CHECK([whether system header files limit the line length], |
110 | [gl_cv_pragma_columns], | |
111 | [dnl HP NonStop systems, which define __TANDEM, have this misfeature. | |
112 | AC_EGREP_CPP([choke me], | |
113 | [ | |
114 | #ifdef __TANDEM | |
115 | choke me | |
116 | #endif | |
117 | ], | |
118 | [gl_cv_pragma_columns=yes], | |
119 | [gl_cv_pragma_columns=no]) | |
120 | ]) | |
121 | if test $gl_cv_pragma_columns = yes; then | |
122 | PRAGMA_COLUMNS="#pragma COLUMNS 10000" | |
123 | else | |
124 | PRAGMA_COLUMNS= | |
125 | fi | |
126 | AC_SUBST([PRAGMA_COLUMNS]) | |
f6ea5628 DJ |
127 | ]) |
128 | ||
129 | # gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...) | |
130 | # ------------------------------------------ | |
131 | # For each arg foo.h, if #include_next works, define NEXT_FOO_H to be | |
132 | # '<foo.h>'; otherwise define it to be | |
133 | # '"///usr/include/foo.h"', or whatever other absolute file name is suitable. | |
f434ba03 PA |
134 | # Also, if #include_next works as first preprocessing directive in a file, |
135 | # define NEXT_AS_FIRST_DIRECTIVE_FOO_H to be '<foo.h>'; otherwise define it to | |
136 | # be | |
137 | # '"///usr/include/foo.h"', or whatever other absolute file name is suitable. | |
f6ea5628 | 138 | # That way, a header file with the following line: |
f434ba03 PA |
139 | # #@INCLUDE_NEXT@ @NEXT_FOO_H@ |
140 | # or | |
141 | # #@INCLUDE_NEXT_AS_FIRST_DIRECTIVE@ @NEXT_AS_FIRST_DIRECTIVE_FOO_H@ | |
f6ea5628 | 142 | # behaves (after sed substitution) as if it contained |
f434ba03 | 143 | # #include_next <foo.h> |
f6ea5628 DJ |
144 | # even if the compiler does not support include_next. |
145 | # The three "///" are to pacify Sun C 5.8, which otherwise would say | |
146 | # "warning: #include of /usr/include/... may be non-portable". | |
770d76d7 | 147 | # Use '""', not '<>', so that the /// cannot be confused with a C99 comment. |
f434ba03 PA |
148 | # Note: This macro assumes that the header file is not empty after |
149 | # preprocessing, i.e. it does not only define preprocessor macros but also | |
150 | # provides some type/enum definitions or function/variable declarations. | |
770d76d7 PA |
151 | # |
152 | # This macro also checks whether each header exists, by invoking | |
153 | # AC_CHECK_HEADERS_ONCE or AC_CHECK_HEADERS on each argument. | |
f6ea5628 | 154 | AC_DEFUN([gl_CHECK_NEXT_HEADERS], |
770d76d7 PA |
155 | [ |
156 | gl_NEXT_HEADERS_INTERNAL([$1], [check]) | |
157 | ]) | |
158 | ||
159 | # gl_NEXT_HEADERS(HEADER1 HEADER2 ...) | |
160 | # ------------------------------------ | |
161 | # Like gl_CHECK_NEXT_HEADERS, except do not check whether the headers exist. | |
162 | # This is suitable for headers like <stddef.h> that are standardized by C89 | |
163 | # and therefore can be assumed to exist. | |
164 | AC_DEFUN([gl_NEXT_HEADERS], | |
165 | [ | |
166 | gl_NEXT_HEADERS_INTERNAL([$1], [assume]) | |
167 | ]) | |
168 | ||
169 | # The guts of gl_CHECK_NEXT_HEADERS and gl_NEXT_HEADERS. | |
170 | AC_DEFUN([gl_NEXT_HEADERS_INTERNAL], | |
f6ea5628 DJ |
171 | [ |
172 | AC_REQUIRE([gl_INCLUDE_NEXT]) | |
f434ba03 | 173 | AC_REQUIRE([AC_CANONICAL_HOST]) |
f6ea5628 | 174 | |
770d76d7 PA |
175 | m4_if([$2], [check], |
176 | [AC_CHECK_HEADERS_ONCE([$1]) | |
177 | ]) | |
178 | ||
179 | dnl FIXME: gl_next_header and gl_header_exists must be used unquoted | |
180 | dnl until we can assume autoconf 2.64 or newer. | |
f434ba03 | 181 | m4_foreach_w([gl_HEADER_NAME], [$1], |
f6ea5628 | 182 | [AS_VAR_PUSHDEF([gl_next_header], |
f434ba03 | 183 | [gl_cv_next_]m4_defn([gl_HEADER_NAME])) |
f6ea5628 | 184 | if test $gl_cv_have_include_next = yes; then |
770d76d7 | 185 | AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>']) |
f6ea5628 DJ |
186 | else |
187 | AC_CACHE_CHECK( | |
f434ba03 PA |
188 | [absolute name of <]m4_defn([gl_HEADER_NAME])[>], |
189 | m4_defn([gl_next_header]), | |
770d76d7 PA |
190 | [m4_if([$2], [check], |
191 | [AS_VAR_PUSHDEF([gl_header_exists], | |
192 | [ac_cv_header_]m4_defn([gl_HEADER_NAME])) | |
193 | if test AS_VAR_GET(gl_header_exists) = yes; then | |
194 | AS_VAR_POPDEF([gl_header_exists]) | |
195 | ]) | |
4a626d0a PA |
196 | gl_ABSOLUTE_HEADER_ONE(gl_HEADER_NAME) |
197 | AS_VAR_COPY([gl_header], [gl_cv_absolute_]AS_TR_SH(gl_HEADER_NAME)) | |
198 | AS_VAR_SET(gl_next_header, ['"'$gl_header'"']) | |
770d76d7 PA |
199 | m4_if([$2], [check], |
200 | [else | |
201 | AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>']) | |
202 | fi | |
203 | ]) | |
204 | ]) | |
f6ea5628 DJ |
205 | fi |
206 | AC_SUBST( | |
f434ba03 | 207 | AS_TR_CPP([NEXT_]m4_defn([gl_HEADER_NAME])), |
770d76d7 | 208 | [AS_VAR_GET(gl_next_header)]) |
f434ba03 PA |
209 | if test $gl_cv_have_include_next = yes || test $gl_cv_have_include_next = buggy; then |
210 | # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include_next' | |
211 | gl_next_as_first_directive='<'gl_HEADER_NAME'>' | |
212 | else | |
213 | # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include' | |
770d76d7 | 214 | gl_next_as_first_directive=AS_VAR_GET(gl_next_header) |
f434ba03 PA |
215 | fi |
216 | AC_SUBST( | |
217 | AS_TR_CPP([NEXT_AS_FIRST_DIRECTIVE_]m4_defn([gl_HEADER_NAME])), | |
218 | [$gl_next_as_first_directive]) | |
f6ea5628 DJ |
219 | AS_VAR_POPDEF([gl_next_header])]) |
220 | ]) | |
770d76d7 PA |
221 | |
222 | # Autoconf 2.68 added warnings for our use of AC_COMPILE_IFELSE; | |
223 | # this fallback is safe for all earlier autoconf versions. | |
224 | m4_define_default([AC_LANG_DEFINES_PROVIDED]) |