-# absolute-header.m4 serial 6
-dnl Copyright (C) 2006 Free Software Foundation, Inc.
+# absolute-header.m4 serial 16
+dnl Copyright (C) 2006-2018 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.
# gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...)
# ---------------------------------------
-# Find the absolute name of a header file, assuming the header exists.
+# Find the absolute name of a header file, testing first if the header exists.
# If the header were sys/inttypes.h, this macro would define
-# ABSOLUTE_SYS_INTTYPES_H to the `""' quoted absolute name of sys/inttypes.h
+# ABSOLUTE_SYS_INTTYPES_H to the '""' quoted absolute name of sys/inttypes.h
# in config.h
-# (e.g. `#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"').
+# (e.g. '#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"').
# 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.
+# 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_ABSOLUTE_HEADER],
-[AC_LANG_PREPROC_REQUIRE()dnl
-AC_FOREACH([gl_HEADER_NAME], [$1],
+[AC_REQUIRE([AC_CANONICAL_HOST])
+AC_LANG_PREPROC_REQUIRE()dnl
+dnl FIXME: gl_absolute_header and ac_header_exists must be used unquoted
+dnl until we can assume autoconf 2.64 or newer.
+m4_foreach_w([gl_HEADER_NAME], [$1],
[AS_VAR_PUSHDEF([gl_absolute_header],
- [gl_cv_absolute_]m4_quote(m4_defn([gl_HEADER_NAME])))dnl
- AC_CACHE_CHECK([absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>],
- m4_quote(m4_defn([gl_absolute_header])),
+ [gl_cv_absolute_]m4_defn([gl_HEADER_NAME]))dnl
+ AC_CACHE_CHECK([absolute name of <]m4_defn([gl_HEADER_NAME])[>],
+ m4_defn([gl_absolute_header]),
[AS_VAR_PUSHDEF([ac_header_exists],
- [ac_cv_header_]m4_quote(m4_defn([gl_HEADER_NAME])))dnl
- AC_CHECK_HEADERS_ONCE(m4_quote(m4_defn([gl_HEADER_NAME])))dnl
+ [ac_cv_header_]m4_defn([gl_HEADER_NAME]))dnl
+ AC_CHECK_HEADERS_ONCE(m4_defn([gl_HEADER_NAME]))dnl
if test AS_VAR_GET(ac_header_exists) = yes; then
- AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]])])
-dnl eval is necessary to expand ac_cpp.
-dnl Ultrix and Pyramid sh refuse to redirect output of eval, so use subshell.
- AS_VAR_SET(gl_absolute_header,
-[`(eval "$ac_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#^/[^/]#//&#;p;q;}'`])
+ gl_ABSOLUTE_HEADER_ONE(m4_defn([gl_HEADER_NAME]))
fi
AS_VAR_POPDEF([ac_header_exists])dnl
])dnl
- AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_quote(m4_defn([gl_HEADER_NAME]))),
+ AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_defn([gl_HEADER_NAME])),
["AS_VAR_GET(gl_absolute_header)"],
- [Define this to an absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>.])
+ [Define this to an absolute name of <]m4_defn([gl_HEADER_NAME])[>.])
AS_VAR_POPDEF([gl_absolute_header])dnl
])dnl
])# gl_ABSOLUTE_HEADER
+
+# gl_ABSOLUTE_HEADER_ONE(HEADER)
+# ------------------------------
+# Like gl_ABSOLUTE_HEADER, except that:
+# - it assumes that the header exists,
+# - it uses the current CPPFLAGS,
+# - it does not cache the result,
+# - it is silent.
+AC_DEFUN([gl_ABSOLUTE_HEADER_ONE],
+[
+ AC_REQUIRE([AC_CANONICAL_HOST])
+ AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote([$1])[[>]])])
+ dnl AIX "xlc -E" and "cc -E" omit #line directives for header files
+ dnl that contain only a #include of other header files and no
+ dnl non-comment tokens of their own. This leads to a failure to
+ dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h>
+ dnl and others. The workaround is to force preservation of comments
+ dnl through option -C. This ensures all necessary #line directives
+ dnl are present. GCC supports option -C as well.
+ case "$host_os" in
+ aix*) gl_absname_cpp="$ac_cpp -C" ;;
+ *) gl_absname_cpp="$ac_cpp" ;;
+ esac
+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'
+ gl_header_literal_regex=`echo '$1' \
+ | sed -e "$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/
+ s|^/[^/]|//&|
+ p
+ q
+ }'
+changequote([,])
+ 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_cv_absolute_]AS_TR_SH([[$1]]),
+[`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
+ sed -n "$gl_absolute_header_sed"`])
+])
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