m4/absolute-header.m4

   1 # absolute-header.m4 serial 8
   2 dnl Copyright (C) 2006-2008 Free Software Foundation, Inc.
   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 Derek Price.
   8
   9 # gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...)
  10 # ---------------------------------------
  11 # Find the absolute name of a header file, assuming the header exists.
  12 # If the header were sys/inttypes.h, this macro would define
  13 # ABSOLUTE_SYS_INTTYPES_H to the `""' quoted absolute name of sys/inttypes.h
  14 # in config.h
  15 # (e.g. `#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"').
  16 # The three "///" are to pacify Sun C 5.8, which otherwise would say
  17 # "warning: #include of /usr/include/... may be non-portable".
  18 # Use `""', not `<>', so that the /// cannot be confused with a C99 comment.
  19 # Note: This macro assumes that the header file is not empty after
  20 # preprocessing, i.e. it does not only define preprocessor macros but also
  21 # provides some type/enum definitions or function/variable declarations.
  22 AC_DEFUN([gl_ABSOLUTE_HEADER],
  23 [AC_LANG_PREPROC_REQUIRE()dnl
  24 AC_FOREACH([gl_HEADER_NAME], [$1],
  25   [AS_VAR_PUSHDEF([gl_absolute_header],
  26                   [gl_cv_absolute_]m4_quote(m4_defn([gl_HEADER_NAME])))dnl
  27   AC_CACHE_CHECK([absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>],
  28     m4_quote(m4_defn([gl_absolute_header])),
  29     [AS_VAR_PUSHDEF([ac_header_exists],
  30                     [ac_cv_header_]m4_quote(m4_defn([gl_HEADER_NAME])))dnl
  31     AC_CHECK_HEADERS_ONCE(m4_quote(m4_defn([gl_HEADER_NAME])))dnl
  32     if test AS_VAR_GET(ac_header_exists) = yes; then
  33       AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]])])
  34 dnl eval is necessary to expand ac_cpp.
  35 dnl Ultrix and Pyramid sh refuse to redirect output of eval, so use subshell.
  36       AS_VAR_SET(gl_absolute_header,
  37 [`(eval "$ac_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
  38 sed -n '\#/]m4_quote(m4_defn([gl_HEADER_NAME]))[#{
  39         s#.*"\(.*/]m4_quote(m4_defn([gl_HEADER_NAME]))[\)".*#\1#
  40         s#^/[^/]#//&#
  41         p
  42         q
  43 }'`])
  44     fi
  45     AS_VAR_POPDEF([ac_header_exists])dnl
  46     ])dnl
  47   AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_quote(m4_defn([gl_HEADER_NAME]))),
  48                      ["AS_VAR_GET(gl_absolute_header)"],
  49                      [Define this to an absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>.])
  50   AS_VAR_POPDEF([gl_absolute_header])dnl
  51 ])dnl
  52 ])# gl_ABSOLUTE_HEADER