| # include_next.m4 serial 23 |
| dnl Copyright (C) 2006-2013 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__'. |
| dnl |
| dnl PRAGMA_COLUMNS can be used in files that override system header files, so |
| dnl as to avoid compilation errors on HP NonStop systems when the gnulib file |
| dnl is included by a system header file that does a "#pragma COLUMNS 80" (which |
| dnl has the effect of truncating the lines of that file and all files that it |
| dnl includes to 80 columns) and the gnulib file has lines longer than 80 |
| dnl columns. |
| |
| 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 conftestd1a conftestd1b conftestd2 |
| mkdir conftestd1a conftestd1b conftestd2 |
| dnl IBM C 9.0, 10.1 (original versions, prior to the 2009-01 updates) on |
| dnl AIX 6.1 support include_next when used as first preprocessor directive |
| dnl in a file, but not when preceded by another include directive. Check |
| dnl for this bug by including <stdio.h>. |
| dnl Additionally, with this same compiler, include_next is a no-op when |
| dnl used in a header file that was included by specifying its absolute |
| dnl file name. Despite these two bugs, include_next is used in the |
| dnl compiler's <math.h>. By virtue of the second bug, we need to use |
| dnl include_next as well in this case. |
| cat <<EOF > conftestd1a/conftest.h |
| #define DEFINED_IN_CONFTESTD1 |
| #include_next <conftest.h> |
| #ifdef DEFINED_IN_CONFTESTD2 |
| int foo; |
| #else |
| #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 |
| gl_save_CPPFLAGS="$CPPFLAGS" |
| CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1b -Iconftestd2" |
| dnl We intentionally avoid using AC_LANG_SOURCE here. |
| AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], |
| [gl_cv_have_include_next=yes], |
| [CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2" |
| AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], |
| [gl_cv_have_include_next=buggy], |
| [gl_cv_have_include_next=no]) |
| ]) |
| CPPFLAGS="$gl_save_CPPFLAGS" |
| rm -rf conftestd1a conftestd1b conftestd2 |
| ]) |
| PRAGMA_SYSTEM_HEADER= |
| if test $gl_cv_have_include_next = yes; then |
| INCLUDE_NEXT=include_next |
| INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next |
| if test -n "$GCC"; then |
| PRAGMA_SYSTEM_HEADER='#pragma GCC system_header' |
| fi |
| else |
| 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]) |
| AC_CACHE_CHECK([whether system header files limit the line length], |
| [gl_cv_pragma_columns], |
| [dnl HP NonStop systems, which define __TANDEM, have this misfeature. |
| AC_EGREP_CPP([choke me], |
| [ |
| #ifdef __TANDEM |
| choke me |
| #endif |
| ], |
| [gl_cv_pragma_columns=yes], |
| [gl_cv_pragma_columns=no]) |
| ]) |
| if test $gl_cv_pragma_columns = yes; then |
| PRAGMA_COLUMNS="#pragma COLUMNS 10000" |
| else |
| PRAGMA_COLUMNS= |
| fi |
| AC_SUBST([PRAGMA_COLUMNS]) |
| ]) |
| |
| # gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...) |
| # ------------------------------------------ |
| # For each arg foo.h, if #include_next works, define NEXT_FOO_H to be |
| # '<foo.h>'; otherwise define it to be |
| # '"///usr/include/foo.h"', or whatever other absolute file name is suitable. |
| # Also, if #include_next works as first preprocessing directive in a file, |
| # define NEXT_AS_FIRST_DIRECTIVE_FOO_H to be '<foo.h>'; otherwise define it to |
| # be |
| # '"///usr/include/foo.h"', or whatever other absolute file name is suitable. |
| # That way, a header file with the following line: |
| # #@INCLUDE_NEXT@ @NEXT_FOO_H@ |
| # or |
| # #@INCLUDE_NEXT_AS_FIRST_DIRECTIVE@ @NEXT_AS_FIRST_DIRECTIVE_FOO_H@ |
| # behaves (after sed substitution) as if it contained |
| # #include_next <foo.h> |
| # even if the compiler does not support include_next. |
| # 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. |
| # |
| # This macro also checks whether each header exists, by invoking |
| # AC_CHECK_HEADERS_ONCE or AC_CHECK_HEADERS on each argument. |
| AC_DEFUN([gl_CHECK_NEXT_HEADERS], |
| [ |
| gl_NEXT_HEADERS_INTERNAL([$1], [check]) |
| ]) |
| |
| # gl_NEXT_HEADERS(HEADER1 HEADER2 ...) |
| # ------------------------------------ |
| # Like gl_CHECK_NEXT_HEADERS, except do not check whether the headers exist. |
| # This is suitable for headers like <stddef.h> that are standardized by C89 |
| # and therefore can be assumed to exist. |
| AC_DEFUN([gl_NEXT_HEADERS], |
| [ |
| gl_NEXT_HEADERS_INTERNAL([$1], [assume]) |
| ]) |
| |
| # The guts of gl_CHECK_NEXT_HEADERS and gl_NEXT_HEADERS. |
| AC_DEFUN([gl_NEXT_HEADERS_INTERNAL], |
| [ |
| AC_REQUIRE([gl_INCLUDE_NEXT]) |
| AC_REQUIRE([AC_CANONICAL_HOST]) |
| |
| m4_if([$2], [check], |
| [AC_CHECK_HEADERS_ONCE([$1]) |
| ]) |
| |
| dnl FIXME: gl_next_header and gl_header_exists must be used unquoted |
| dnl until we can assume autoconf 2.64 or newer. |
| m4_foreach_w([gl_HEADER_NAME], [$1], |
| [AS_VAR_PUSHDEF([gl_next_header], |
| [gl_cv_next_]m4_defn([gl_HEADER_NAME])) |
| if test $gl_cv_have_include_next = yes; then |
| AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>']) |
| else |
| AC_CACHE_CHECK( |
| [absolute name of <]m4_defn([gl_HEADER_NAME])[>], |
| m4_defn([gl_next_header]), |
| [m4_if([$2], [check], |
| [AS_VAR_PUSHDEF([gl_header_exists], |
| [ac_cv_header_]m4_defn([gl_HEADER_NAME])) |
| if test AS_VAR_GET(gl_header_exists) = yes; then |
| AS_VAR_POPDEF([gl_header_exists]) |
| ]) |
| AC_LANG_CONFTEST( |
| [AC_LANG_SOURCE( |
| [[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]] |
| )]) |
| dnl AIX "xlc -E" and "cc -E" omit #line directives for header |
| dnl files that contain only a #include of other header files and |
| dnl no non-comment tokens of their own. This leads to a failure |
| dnl to detect the absolute name of <dirent.h>, <signal.h>, |
| dnl <poll.h> and others. The workaround is to force preservation |
| dnl of comments through option -C. This ensures all necessary |
| dnl #line directives are present. GCC supports option -C as well. |
| case "$host_os" in |
| aix*) gl_absname_cpp="$ac_cpp -C" ;; |
| *) gl_absname_cpp="$ac_cpp" ;; |
| esac |
| changequote(,) |
| case "$host_os" in |
| mingw*) |
| dnl For the sake of native Windows compilers (excluding gcc), |
| dnl treat backslash as a directory separator, like /. |
| dnl Actually, these compilers use a double-backslash as |
| dnl directory separator, inside the |
| dnl # line "filename" |
| dnl directives. |
| gl_dirsep_regex='[/\\]' |
| ;; |
| *) |
| gl_dirsep_regex='\/' |
| ;; |
| esac |
| dnl A sed expression that turns a string into a basic regular |
| dnl expression, for use within "/.../". |
| gl_make_literal_regex_sed='s,[]$^\\.*/[],\\&,g' |
| changequote([,]) |
| gl_header_literal_regex=`echo ']m4_defn([gl_HEADER_NAME])[' \ |
| | sed -e "$gl_make_literal_regex_sed"` |
| gl_absolute_header_sed="/${gl_dirsep_regex}${gl_header_literal_regex}/"'{ |
| s/.*"\(.*'"${gl_dirsep_regex}${gl_header_literal_regex}"'\)".*/\1/ |
| changequote(,)dnl |
| s|^/[^/]|//&| |
| changequote([,])dnl |
| p |
| q |
| }' |
| 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 "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD | |
| sed -n "$gl_absolute_header_sed"`'"']) |
| m4_if([$2], [check], |
| [else |
| AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>']) |
| fi |
| ]) |
| ]) |
| fi |
| AC_SUBST( |
| AS_TR_CPP([NEXT_]m4_defn([gl_HEADER_NAME])), |
| [AS_VAR_GET(gl_next_header)]) |
| if test $gl_cv_have_include_next = yes || test $gl_cv_have_include_next = buggy; then |
| # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include_next' |
| gl_next_as_first_directive='<'gl_HEADER_NAME'>' |
| else |
| # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include' |
| gl_next_as_first_directive=AS_VAR_GET(gl_next_header) |
| fi |
| AC_SUBST( |
| AS_TR_CPP([NEXT_AS_FIRST_DIRECTIVE_]m4_defn([gl_HEADER_NAME])), |
| [$gl_next_as_first_directive]) |
| AS_VAR_POPDEF([gl_next_header])]) |
| ]) |
| |
| # Autoconf 2.68 added warnings for our use of AC_COMPILE_IFELSE; |
| # this fallback is safe for all earlier autoconf versions. |
| m4_define_default([AC_LANG_DEFINES_PROVIDED]) |
