net: Add NET_API to net/base

base/compiler_specific.h

Index: base/compiler_specific.h
===================================================================
--- base/compiler_specific.h	(revision 85332)
+++ base/compiler_specific.h	(working copy)
@@ -54,6 +54,19 @@
                                              code \
                                              MSVC_POP_WARNING()
 
+// Allows exporting a class that inherits from a non-exported base class.
+// This uses suppress instead of push/pop because the delimiter after the
+// declaration (either "," or "{") has to be placed before the pop macro.
+//
+// Example usage:
+// Class EXPORT_API Foo : NON_EXPORTED_BASE(public Bar) {

[brettw, 2011/05/18 06:06:18]

Did you mean "Class" to be lower-case?

[rvargas (doing something else), 2011/05/18 18:13:48]

Yes, fixed.

+//
+// MSVC Compiler warning C4275:
+// non dll-interface class 'Bar' used as base for dll-interface class 'Foo'
+// http://msdn.microsoft.com/en-us/library/3c594ae3(VS.80).aspx

[brettw, 2011/05/18 06:06:18]

Your URL doesn't seem to talk about C4275. I searched and found this page, is it
the right one?
http://msdn.microsoft.com/en-us/library/3tdb471s(VS.80).aspx

It might also be good to mention that you need to be very careful if you have
static data in the base class, and to see the article for more.

[rvargas (doing something else), 2011/05/18 18:13:48]

I added this to the comment:
// Note that this is intended to be used only when no access to the base class
// can be gained through the derived class. For more info, see
// http://msdn.microsoft.com/en-us/library/3tdb471s(VS.80).aspx

+#define NON_EXPORTED_BASE(code) MSVC_SUPPRESS_WARNING(4275) \
+                                code
+
 #else  // Not MSVC
 
 #define MSVC_SUPPRESS_WARNING(n)
@@ -63,6 +76,7 @@
 #define MSVC_DISABLE_OPTIMIZE()
 #define MSVC_ENABLE_OPTIMIZE()
 #define ALLOW_THIS_IN_INITIALIZER_LIST(code) code
+#define NON_EXPORTED_BASE(code) code
 
 #endif  // COMPILER_MSVC