-# include_next.m4 serial 1
-dnl Copyright (C) 2006 Free Software Foundation, Inc.
+# include_next.m4 serial 23
+dnl Copyright (C) 2006-2014 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 Derek Price.
+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_CACHE_CHECK([whether the preprocessor supports include_next],
-[gl_cv_have_include_next],
-[AC_PREPROC_IFELSE([#include_next <stddef.h>],
- [gl_cv_have_include_next=yes],
- [gl_cv_have_include_next=no])])
-if test $gl_cv_have_include_next = yes; then
- AC_DEFINE([HAVE_INCLUDE_NEXT], 1,
- [Define if your compiler supports the #include_next directive.])
-fi
+[
+ AC_LANG_PREPROC_REQUIRE()
+ AC_CACHE_CHECK([whether the preprocessor supports include_next],
+ [gl_cv_have_include_next],
+ [rm -rf conftestd1a conftestd1b conftestd2
+ mkdir conftestd1a conftestd1b conftestd2
+ dnl IBM C 9.0, 10.1 (original versions, prior to the 2009-01 updates) on
+ dnl AIX 6.1 support include_next when used as first preprocessor directive
+ dnl in a file, but not when preceded by another include directive. Check
+ dnl for this bug by including <stdio.h>.
+ dnl Additionally, with this same compiler, include_next is a no-op when
+ dnl used in a header file that was included by specifying its absolute
+ dnl file name. Despite these two bugs, include_next is used in the
+ dnl compiler's <math.h>. By virtue of the second bug, we need to use
+ dnl include_next as well in this case.
+ cat <<EOF > conftestd1a/conftest.h
+#define DEFINED_IN_CONFTESTD1
+#include_next <conftest.h>
+#ifdef DEFINED_IN_CONFTESTD2
+int foo;
+#else
+#error "include_next doesn't work"
+#endif
+EOF
+ cat <<EOF > conftestd1b/conftest.h
+#define DEFINED_IN_CONFTESTD1
+#include <stdio.h>
+#include_next <conftest.h>
+#ifdef DEFINED_IN_CONFTESTD2
+int foo;
+#else
+#error "include_next doesn't work"
+#endif
+EOF
+ cat <<EOF > conftestd2/conftest.h
+#ifndef DEFINED_IN_CONFTESTD1
+#error "include_next test doesn't work"
+#endif
+#define DEFINED_IN_CONFTESTD2
+EOF
+ gl_save_CPPFLAGS="$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([$2], [check],
+ [AS_VAR_PUSHDEF([gl_header_exists],
+ [ac_cv_header_]m4_defn([gl_HEADER_NAME]))
+ if test AS_VAR_GET(gl_header_exists) = yes; then
+ AS_VAR_POPDEF([gl_header_exists])
+ ])
+ gl_ABSOLUTE_HEADER_ONE(gl_HEADER_NAME)
+ AS_VAR_COPY([gl_header], [gl_cv_absolute_]AS_TR_SH(gl_HEADER_NAME))
+ AS_VAR_SET(gl_next_header, ['"'$gl_header'"'])
+ 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])
projects / gnulib.git / blobdiff