Added compiler feature detection for __VA_ARGS__ and GCC ##__VA_ARGS__

Made macro names more explicit to prevent name conflicts

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@1815 7f0cb862-5218-0410-a997-914c9d46530a

diff --git a/src/fg_callback_macros.h b/src/fg_callback_macros.h
index 2406243..76c7227 100644 (file)
--- a/src/fg_callback_macros.h
+++ b/src/fg_callback_macros.h
@@ -27,16 +27,33 @@
 #ifndef FREEGLUT_CALLBACK_MACROS_H
 #define FREEGLUT_CALLBACK_MACROS_H
 
-#ifndef FREEGLUT_INTERNAL_H
-#error "fg_internal.h needs to be included before this header"
-#endif
-
 /*
  * Compiler defines:
- * FG_COMPILER_SUPPORTS_GCC_VA_ARGS_HACK: if the compiler supports GCC's varadic macro implementation (AKA, ##__VA_ARGS__)
- * FG_COMPILER_SUPPORTS_VA_ARGS: if the compiler supports varadic macros
+ * FG_COMPILER_SUPPORTS_GCC_VA_ARGS_HACK: if the compiler supports GCC's variadic macro implementation (AKA, ##__VA_ARGS__)
+ * FG_COMPILER_SUPPORTS_VA_ARGS: if the compiler supports variadic macros
  */
 
+/* What supports variadic macros based off Wikipedia article on it */
+#if (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || \
+       (defined(__GNUC__) && (__GNUC__ >= 3)) || \
+       (defined(__clang__)) || \
+       (defined(_MSC_VER) && (_MSC_VER >= 1400)) || \
+       (defined(__BORLANDC__) && (__BORLANDC__ >= 0x570)) || \
+       (defined(__SUNPRO_C) && (__SUNPRO_C >= 0x530))
+#define FG_COMPILER_SUPPORTS_VA_ARGS 1
+#else
+#define FG_COMPILER_SUPPORTS_VA_ARGS 0
+#endif
+
+/* If __VA_ARGS__ is supported, it needs to be GCC(-like) or Clang (since Clang mimics GCC) */
+#if FG_COMPILER_SUPPORTS_VA_ARGS && \
+       (defined(__GNUC__)) || \
+       (defined(__clang__))
+#define FG_COMPILER_SUPPORTS_GCC_VA_ARGS_HACK 1
+#else
+#define FG_COMPILER_SUPPORTS_GCC_VA_ARGS_HACK 0
+#endif
+
 /*
  * Info:
  *
@@ -58,20 +75,20 @@
  * There is one for GCC/Clang(/and supposedly the Intel compiler) which supports the non-standard ##__VA_ARGS__ token. The code may 
  * look ugly, but the result is, if this was standard, no one would ever need to open this file unless they were curious (or needed 
  * more then 5 arguments for a callback, but that's trivial to add). It works by adding many fake macros to a "picker" macro
- * (PP_HAS_ARGS_IMPL2) which then indictaes which macro counter to use. As we can already use varadic macros (the VA in __VA_ARGS__),
+ * (PP_HAS_ARGS_IMPL2) which then indictaes which macro counter to use. As we can already use variadic macros (the VA in __VA_ARGS__),
  * this just becomes a "reuse the arguments*.
  * 
  * The next is for any non-GCC/Clang/etc. compiler *cough* MSVC/compiler you probably shouldn't be using *cough* that supports C99
  * by default. It requires each callback to have a specific argument count passthrough macro. The only reason there are specific
  * count macros is so that (see paraghraph below) don't need have their own set of callback macros. Ideally, there would only be
  * ZERO and ONE_OR_MORE. This works by having callback-specific macros call a specific handler macro to return user data (ZERO) or
- * return one or more arguments along with userData (ONE_OR_MORE) where, with varadic macros, it just reuses the arguments.
+ * return one or more arguments along with userData (ONE_OR_MORE) where, with variadic macros, it just reuses the arguments.
  *
  * The last set is for the poor individual who has to use a compiler that doesn't support C99 by default, or may not support it at
  * all. Stuff like MSVC6... It works by having a specific-count macro that "extracts" each argument to have them reused without the
  * parathesis.
  *
- * A note on parathesis, as earlier mentioned, if the GCC varadic macro element was standard, then instead of needing:
+ * A note on parathesis, as earlier mentioned, if the GCC variadic macro element was standard, then instead of needing:
  *
  * func EXPAND_WCB(Mouse)(( (GLUT_LEFT_BUTTON, GLUT_DOWN, 10, 30), userData));
  *
@@ -84,7 +101,7 @@
  * implicitly passes "userData" and only works on GCC vardiac macro supporting compilers.
  */
 
-#ifdef FG_COMPILER_SUPPORTS_GCC_VA_ARGS_HACK
+#if FG_COMPILER_SUPPORTS_GCC_VA_ARGS_HACK
 
  /*
  * EXPAND_WCB() is used as:
@@ -108,19 +125,19 @@
  * should not require any modification unless additional arguments are to 
  * be supported.
  * 
- * Supports callbacks up to 5 args (follow the pattern of PP_HAS_ARGS_IMPL2
- * and PP_HAS_ARGS_SOURCE to add more)
+ * Supports callbacks up to 5 args (follow the pattern of 
+ * EXPAND_WCB_PP_HAS_ARGS_IMPL2 and EXPAND_WCB_PP_HAS_ARGS_SOURCE to add more)
  *
  * Edit with care.
  */
 
 #define EXPAND_WCB_UNPARAN(...) __VA_ARGS__
 
-#define PP_HAS_ARGS_IMPL2(_0, _1, _2, _3, _4, _5, N, ...) N
-#define PP_HAS_ARGS_SOURCE() ONE_OR_MORE, ONE_OR_MORE, ONE_OR_MORE, ONE_OR_MORE, ONE_OR_MORE, ZERO
+#define EXPAND_WCB_PP_HAS_ARGS_IMPL2(_0, _1, _2, _3, _4, _5, N, ...) N
+#define EXPAND_WCB_PP_HAS_ARGS_SOURCE() ONE_OR_MORE, ONE_OR_MORE, ONE_OR_MORE, ONE_OR_MORE, ONE_OR_MORE, ZERO
 
-#define PP_HAS_ARGS_IMPL(...) PP_HAS_ARGS_IMPL2( __VA_ARGS__ )
-#define PP_HAS_ARGS(...) PP_HAS_ARGS_IMPL( NOT_EXIST, ##__VA_ARGS__, PP_HAS_ARGS_SOURCE() )
+#define EXPAND_WCB_PP_HAS_ARGS_IMPL(...) EXPAND_WCB_PP_HAS_ARGS_IMPL2( __VA_ARGS__ )
+#define EXPAND_WCB_PP_HAS_ARGS(...) EXPAND_WCB_PP_HAS_ARGS_IMPL( NOT_EXIST, ##__VA_ARGS__, EXPAND_WCB_PP_HAS_ARGS_SOURCE() )
 
 #define EXPAND_WCB_ZERO(args, userData) ( userData )
 #define EXPAND_WCB_ONE_OR_MORE(args, userData) ( EXPAND_WCB_UNPARAN args, userData )
@@ -128,7 +145,7 @@
 #define EXPAND_WCB_DISAMBIGUATE2(has_args, args, userData) EXPAND_WCB_ ## has_args ( args, userData )
 #define EXPAND_WCB_DISAMBIGUATE(has_args, args, userData) EXPAND_WCB_DISAMBIGUATE2( has_args, args, userData )
 
-#define EXPAND_WCB_UNWRAP_ARGS2(args, userData) EXPAND_WCB_DISAMBIGUATE( PP_HAS_ARGS args, args, userData )
+#define EXPAND_WCB_UNWRAP_ARGS2(args, userData) EXPAND_WCB_DISAMBIGUATE( EXPAND_WCB_PP_HAS_ARGS args, args, userData )
 #define EXPAND_WCB_UNWRAP_ARGS(args) EXPAND_WCB_UNWRAP_ARGS2 args
 
 #define EXPAND_WCB(cbname) EXPAND_WCB_UNWRAP_ARGS
@@ -159,7 +176,7 @@
  * #define EXPAND_WCB_SUB_Entry(args) EXPAND_WCB_ONE args
  */
 
-#ifdef FG_COMPILER_SUPPORTS_VA_ARGS
+#if FG_COMPILER_SUPPORTS_VA_ARGS
 
 #define EXPAND_WCB_UNPARAN(...) __VA_ARGS__
 #define EXPAND_WCB_ONE_OR_MORE(args, userData) ( EXPAND_WCB_UNPARAN args, userData )
@@ -172,17 +189,17 @@
 
 #else
 
-#define EXTRACT_ONE_ARGS(arg1) arg1
-#define EXTRACT_TWO_ARGS(arg1, arg2) arg1, arg2
-#define EXTRACT_THREE_ARGS(arg1, arg2, arg3) arg1, arg2, arg3
-#define EXTRACT_FOUR_ARGS(arg1, arg2, arg3, arg4) arg1, arg2, arg3, arg4
-#define EXTRACT_FIVE_ARGS(arg1, arg2, arg3, arg4, arg5) arg1, arg2, arg3, arg4, arg5
-
-#define EXPAND_WCB_ONE(args, userData) (EXTRACT_ONE_ARGS args, userData)
-#define EXPAND_WCB_TWO(args, userData) (EXTRACT_TWO_ARGS args, userData)
-#define EXPAND_WCB_THREE(args, userData) (EXTRACT_THREE_ARGS args, userData)
-#define EXPAND_WCB_FOUR(args, userData) (EXTRACT_FOUR_ARGS args, userData)
-#define EXPAND_WCB_FIVE(args, userData) (EXTRACT_FIVE_ARGS args, userData)
+#define EXPAND_WCB_EXTRACT_ONE_ARGS(arg1) arg1
+#define EXPAND_WCB_EXTRACT_TWO_ARGS(arg1, arg2) arg1, arg2
+#define EXPAND_WCB_EXTRACT_THREE_ARGS(arg1, arg2, arg3) arg1, arg2, arg3
+#define EXPAND_WCB_EXTRACT_FOUR_ARGS(arg1, arg2, arg3, arg4) arg1, arg2, arg3, arg4
+#define EXPAND_WCB_EXTRACT_FIVE_ARGS(arg1, arg2, arg3, arg4, arg5) arg1, arg2, arg3, arg4, arg5
+
+#define EXPAND_WCB_ONE(args, userData) (EXPAND_WCB_EXTRACT_ONE_ARGS args, userData)
+#define EXPAND_WCB_TWO(args, userData) (EXPAND_WCB_EXTRACT_TWO_ARGS args, userData)
+#define EXPAND_WCB_THREE(args, userData) (EXPAND_WCB_EXTRACT_THREE_ARGS args, userData)
+#define EXPAND_WCB_FOUR(args, userData) (EXPAND_WCB_EXTRACT_FOUR_ARGS args, userData)
+#define EXPAND_WCB_FIVE(args, userData) (EXPAND_WCB_EXTRACT_FIVE_ARGS args, userData)
 
 #endif