dispatch-1.0/m4/private-extern.m4

   1 #
   2 # Does the platform support __private_extern__?  There is surely a better way
   3 # to check this.
   4 #
   5 AC_DEFUN([DISPATCH_C_PRIVATE_EXTERN], [
   6
   7 AC_CACHE_CHECK([for __attribute__((visibility("hidden")))],
   8     dispatch_cv_hidden_visibility_attribute, [
   9         AC_TRY_LINK([],
  10                     [extern __attribute__ ((visibility ("hidden"))) int foo;],
  11                     [dispatch_cv_hidden_visibility_attribute=yes],
  12                     [dispatch_cv_hidden_visibility_attribute=no])])
  13
  14 AC_CACHE_CHECK([for __private_extern__],
  15     dispatch_cv_private_extern, [
  16         AC_TRY_LINK([], [__private_extern__ int foo;],
  17                     [dispatch_cv_private_extern=yes],
  18                     [dispatch_cv_private_extern=no])])
  19
  20 if test $dispatch_cv_private_extern = yes; then
  21   AC_DEFINE(HAVE_PRIVATE_EXTERN, 1, Define if __private_extern__ present)
  22 elif test $dispatch_cv_hidden_visibility_attribute = yes; then
  23   AC_DEFINE(HAVE_PRIVATE_EXTERN, 1, Define if __private_extern__ present)
  24   AC_DEFINE([__private_extern__], [extern __attribute__ ((visibility ("hidden")))],
  25             [Define to a replacement for __private_extern])
  26 else
  27   AC_DEFINE([__private_extern__], [extern],
  28             [Define to a replacement for __private_extern])
  29 fi
  30
  31 ])