AX_EXT_CHECK_HEADER(<header>, <paths>).
, 

2005-01-21

Duncan Simpson <dps@simpson.demon.co.uk>

AllPermissive
Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. Users of this software should generally follow the principles of the MIT License includings its disclaimer.

cryp.to ac-archive's Installed Packages (released)

Check for <header> with -I<path> for each path in <paths> if need be. The first sucecssful path is chosen (eg if you say AX_EXT_CHECK_HEADER(foo.h, bar baz qux) and -Ibaz works then -Iqux will not be tested.

Any -I flags that locate a header are added to CFLAGS and CPPFLAGS. AS with AC_CHECK_HEADERS it causes HAVE_<header>_H to be defined as 1.

Example:

AX_EXT_HAVE_HEADER(openssl/rsa.h, /usr/local/include /usr/local/ssl/include /usr/local/openssl/include)

AC_DEFUN([AX_EXT_HAVE_HEADER],
[AC_LANG_PUSH(C)
 AC_CHECK_HEADER($1, [$3 got="yes"], [$4 got="no"], $5)
 hdr=`echo $1 | $as_tr_sh`
 for dir in $2; do
  if test "x${got}" = "xno"; then
   ext_hashdr_cvdir=`echo $dir | $as_tr_sh`
   AC_CACHE_CHECK([for $1 library with -I$dir],
    [ext_cv${ext_hashdr_cvdir}_hashdr_${hdr}],
    [ext_have_hdr_save_cflags=${CFLAGS}
     CFLAGS="${CFLAGS} -I${dir}"
     AC_COMPILE_IFELSE(
      [AC_LANG_PROGRAM([#inc[]lude <$1>])],
       [got="yes"; eval "ext_cv${ext_hashdr_cvdir}_hashdr_${hdr}"="yes"],
       [got="no"; eval "ext_cv${ext_hashdr_cvdir}_hashdr_${hdr}"="no"])
      CFLAGS=$ext_have_hdr_save_cflags])
     if eval `echo 'test x${'ext_cv${ext_hashdr_cvdir}_hashdr_${hdr}'}' = "xyes"`; then
      CFLAGS="${CFLAGS} -I${dir}"
      CPPFLAGS="${CPPFLAGS} -I${dir}"
      got="yes";
      hdr=`echo $1 | $as_tr_cpp`
      AC_DEFINE_UNQUOTED(HAVE_${hdr}, 1,
       [Define this if you have the $1 header])
  fi; fi; done
AC_LANG_POP])