diff options
Diffstat (limited to 'gl/m4/include_next.m4')
| -rw-r--r-- | gl/m4/include_next.m4 | 103 |
1 files changed, 83 insertions, 20 deletions
diff --git a/gl/m4/include_next.m4 b/gl/m4/include_next.m4 index 7ce472bc..062753c5 100644 --- a/gl/m4/include_next.m4 +++ b/gl/m4/include_next.m4 @@ -1,19 +1,46 @@ -# include_next.m4 serial 4 -dnl Copyright (C) 2006, 2007 Free Software Foundation, Inc. +# include_next.m4 serial 10 +dnl Copyright (C) 2006-2008 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. dnl From Paul Eggert and Derek Price. +dnl Sets INCLUDE_NEXT and PRAGMA_SYSTEM_HEADER. +dnl +dnl INCLUDE_NEXT expands to 'include_next' if the compiler supports it, or to +dnl 'include' otherwise. +dnl +dnl INCLUDE_NEXT_AS_FIRST_DIRECTIVE expands to 'include_next' if the compiler +dnl supports it in the special case that it is the first include directive in +dnl the given file, or to 'include' otherwise. +dnl +dnl PRAGMA_SYSTEM_HEADER can be used in files that contain #include_next, +dnl so as to avoid GCC warnings when the gcc option -pedantic is used. +dnl '#pragma GCC system_header' has the same effect as if the file was found +dnl through the include search path specified with '-isystem' options (as +dnl opposed to the search path specified with '-I' options). Namely, gcc +dnl does not warn about some things, and on some systems (Solaris and Interix) +dnl __STDC__ evaluates to 0 instead of to 1. The latter is an undesired side +dnl effect; we are therefore careful to use 'defined __STDC__' or '1' instead +dnl of plain '__STDC__'. + AC_DEFUN([gl_INCLUDE_NEXT], [ AC_LANG_PREPROC_REQUIRE() AC_CACHE_CHECK([whether the preprocessor supports include_next], [gl_cv_have_include_next], - [rm -rf conftestd1 conftestd2 - mkdir conftestd1 conftestd2 - cat <<EOF > conftestd1/conftest.h + [rm -rf conftestd1a conftestd1b conftestd2 + mkdir conftestd1a conftestd1b conftestd2 + dnl The include of <stdio.h> is because IBM C 9.0 on AIX 6.1 supports + dnl include_next when used as first preprocessor directive in a file, + dnl but not when preceded by another include directive. Additionally, + dnl with this same compiler, include_next is a no-op when used in a + dnl header file that was included by specifying its absolute file name. + dnl Despite these two bugs, include_next is used in the compiler's + dnl <math.h>. By virtue of the second bug, we need to use include_next + dnl as well in this case. + cat <<EOF > conftestd1a/conftest.h #define DEFINED_IN_CONFTESTD1 #include_next <conftest.h> #ifdef DEFINED_IN_CONFTESTD2 @@ -22,32 +49,53 @@ int foo; #error "include_next doesn't work" #endif EOF + cat <<EOF > conftestd1b/conftest.h +#define DEFINED_IN_CONFTESTD1 +#include <stdio.h> +#include_next <conftest.h> +#ifdef DEFINED_IN_CONFTESTD2 +int foo; +#else +#error "include_next doesn't work" +#endif +EOF cat <<EOF > conftestd2/conftest.h #ifndef DEFINED_IN_CONFTESTD1 #error "include_next test doesn't work" #endif #define DEFINED_IN_CONFTESTD2 EOF - save_CPPFLAGS="$CPPFLAGS" - CPPFLAGS="$CPPFLAGS -Iconftestd1 -Iconftestd2" + gl_save_CPPFLAGS="$CPPFLAGS" + CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1b -Iconftestd2" AC_COMPILE_IFELSE([#include <conftest.h>], [gl_cv_have_include_next=yes], - [gl_cv_have_include_next=no]) - CPPFLAGS="$save_CPPFLAGS" - rm -rf conftestd1 conftestd2 + [CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2" + AC_COMPILE_IFELSE([#include <conftest.h>], + [gl_cv_have_include_next=buggy], + [gl_cv_have_include_next=no]) + ]) + CPPFLAGS="$gl_save_CPPFLAGS" + rm -rf conftestd1a conftestd1b conftestd2 ]) + PRAGMA_SYSTEM_HEADER= if test $gl_cv_have_include_next = yes; then - - dnl FIXME: Remove HAVE_INCLUDE_NEXT and update everything that uses it - dnl to use @INCLUDE_NEXT@ instead. - AC_DEFINE([HAVE_INCLUDE_NEXT], 1, - [Define if your compiler supports the #include_next directive.]) - INCLUDE_NEXT=include_next + INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next + if test -n "$GCC"; then + PRAGMA_SYSTEM_HEADER='#pragma GCC system_header' + fi else - INCLUDE_NEXT=include + if test $gl_cv_have_include_next = buggy; then + INCLUDE_NEXT=include + INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next + else + INCLUDE_NEXT=include + INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include + fi fi AC_SUBST([INCLUDE_NEXT]) + AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE]) + AC_SUBST([PRAGMA_SYSTEM_HEADER]) ]) # gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...) @@ -63,12 +111,16 @@ EOF # The three "///" are to pacify Sun C 5.8, which otherwise would say # "warning: #include of /usr/include/... may be non-portable". # Use `""', not `<>', so that the /// cannot be confused with a C99 comment. +# Note: This macro assumes that the header file is not empty after +# preprocessing, i.e. it does not only define preprocessor macros but also +# provides some type/enum definitions or function/variable declarations. AC_DEFUN([gl_CHECK_NEXT_HEADERS], [ AC_REQUIRE([gl_INCLUDE_NEXT]) + AC_REQUIRE([AC_CANONICAL_HOST]) AC_CHECK_HEADERS_ONCE([$1]) - AC_FOREACH([gl_HEADER_NAME], [$1], + m4_foreach_w([gl_HEADER_NAME], [$1], [AS_VAR_PUSHDEF([gl_next_header], [gl_cv_next_]m4_quote(m4_defn([gl_HEADER_NAME]))) if test $gl_cv_have_include_next = yes; then @@ -84,11 +136,22 @@ AC_DEFUN([gl_CHECK_NEXT_HEADERS], [AC_LANG_SOURCE( [[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]] )]) - dnl eval is necessary to expand ac_cpp. + dnl AIX "xlc -E" and "cc -E" omit #line directives for header files + dnl that contain only a #include of other header files and no + dnl non-comment tokens of their own. This leads to a failure to + dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h> + dnl and others. The workaround is to force preservation of comments + dnl through option -C. This ensures all necessary #line directives + dnl are present. GCC supports option -C as well. + case "$host_os" in + aix*) gl_absname_cpp="$ac_cpp -C" ;; + *) gl_absname_cpp="$ac_cpp" ;; + esac + dnl eval is necessary to expand gl_absname_cpp. dnl Ultrix and Pyramid sh refuse to redirect output of eval, dnl so use subshell. AS_VAR_SET([gl_next_header], - ['"'`(eval "$ac_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD | + ['"'`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD | sed -n '\#/]m4_quote(m4_defn([gl_HEADER_NAME]))[#{ s#.*"\(.*/]m4_quote(m4_defn([gl_HEADER_NAME]))[\)".*#\1# s#^/[^/]#//&# |