Certain headers, such as signal.h, use enum values instead of preprocessor constants.  However, these values are not
necessarily supported across platforms.  For example, the idtype_t enum in signal.h on Solaris 9 has a P_PROJID member
that is only defined on Solaris 8 or later.

To allow programmers to check for the presence of certain enum members, I propose a "have_enum_member" method
as follows:

--- mkmf.bak    Fri Feb 11 08:30:47 2005
+++ mkmf.rb     Fri Feb 11 09:33:47 2005
@@ -552,6 +552,23 @@
   end
 end
 
+def have_enum_member(type, member, header = nil, &b)
+  checking_for "#{type}.#{member}" do
+    if try_compile(<<"SRC", &b)
+#{COMMON_HEADERS}
+#{cpp_include(header)}
+/*top*/
+static #{type} t;
+int s = #{member};
+SRC
+      $defs.push(format("-DHAVE_ENUM_%s", member.upcase))
+      true
+    else
+      false
+    end
+  end
+end
+
 def have_type(type, header = nil, opt = "", &b)
   checking_for type do
     header = cpp_include(header)

This would then create a HAVE_ENUM_XXX preprocessor constant programmers could use within their extensions.

Regards,

Dan

Date: 2007-09-21 21:35
Sender: Nobuyoshi Nakada 

have_const was added instead.