Header File for TAO_IDL Supported IDL Features

Get information about what IDL features the IDL compiler has, similarly
to the "version" standard header in C++.

In C++ it can be used like this if you want to be compatible with older
versions of TAO:

```c++
 #include "tao/orbconf.h"
 #if defined TAO_HAS_IDL_FEATURES && TAO_HAS_IDL_FEATURES
 // Use this macro if you are using something that's not the max possible
 // version.
 #  define TAO_IDL_IDL_VERSION 0x50000
 #  include "tao/idl_features.h"
 #  define USE_FEATURE defined TAO_IDL_HAS_FEATURE && TAO_IDL_HAS_FEATURE
 #else
 #  define USE_FEATURE 0
 #endif
```

In IDL it can be used like this if you want to be compatible with older
versions of TAO:

```c++
 #if defined __TAO_IDL_FEATURES
 #  include __TAO_IDL_FEATURES
 #  define USE_FEATURE defined TAO_IDL_HAS_FEATURE && TAO_IDL_HAS_FEATURE
 #else
 #  define USE_FEATURE 0
 #endif
```

3 files changed, 80 insertions, 0 deletions

diff --git a/TAO/tao/idl_features.h b/TAO/tao/idl_features.h
new file mode 100644
index 00000000000..40cc7d951b8
--- /dev/null
+++ b/TAO/tao/idl_features.h
@@ -0,0 +1,75 @@
+/**
+ * @file idl_features.h
+ *
+ * Get information about what IDL features the IDL compiler has, similarly to
+ * the "version" standard header in C++.
+ *
+ * In C++ it can be used like this if you want to be compatible with older
+ * versions of TAO:
+ *
+ * #include "tao/orbconf.h"
+ * #if defined TAO_HAS_IDL_FEATURES && TAO_HAS_IDL_FEATURES
+ * // Use this macro if you are using something that's not the max possible
+ * // version.
+ * #  define TAO_IDL_IDL_VERSION 0x30000
+ * #  include "tao/idl_features.h"
+ * #  define USE_FEATURE defined TAO_IDL_HAS_FEATURE && TAO_IDL_HAS_FEATURE
+ * #else
+ * #  define USE_FEATURE 0
+ * #endif
+ *
+ * In IDL it can be used like this if you want to be compatible with older
+ * versions of TAO:
+ *
+ * #if defined __TAO_IDL_FEATURES
+ * #  include __TAO_IDL_FEATURES
+ * #  define USE_FEATURE defined TAO_IDL_HAS_FEATURE && TAO_IDL_HAS_FEATURE
+ * #else
+ * #  define USE_FEATURE 0
+ * #endif
+ */
+
+#ifndef TAO_IDL_FEATURES_H
+#define TAO_IDL_FEATURES_H
+
+#ifndef TAO_IDL_IDL_VERSION
+#  ifdef __TAO_IDL_IDL_VERSION
+#    define TAO_IDL_IDL_VERSION __TAO_IDL_IDL_VERSION
+#  else
+#    define TAO_IDL_IDL_VERSION 0xffffffff
+#  endif
+#endif
+
+#ifndef TAO_IDL_HAS_ANNOTATIONS
+#  define TAO_IDL_HAS_ANNOTATIONS TAO_IDL_IDL_VERSION >= 0x40000
+#endif
+
+#ifndef TAO_IDL_HAS_ANONYMOUS_TYPES
+#  define TAO_IDL_HAS_ANONYMOUS_TYPES TAO_IDL_IDL_VERSION >= 0x40000
+#endif
+
+#ifndef TAO_IDL_HAS_EXPLICIT_INTS
+#  define TAO_IDL_HAS_EXPLICIT_INTS TAO_IDL_IDL_VERSION >= 0x40000
+#endif
+
+#ifndef TAO_IDL_HAS_OCTET_AND_WCHAR_UNION_DISCS
+#  define TAO_IDL_HAS_OCTET_AND_WCHAR_UNION_DISCS 0
+#endif
+
+#ifndef TAO_IDL_HAS_STRUCT_INHERITANCE
+#  define TAO_IDL_HAS_STRUCT_INHERITANCE 0
+#endif
+
+#ifndef TAO_IDL_HAS_MAP
+#  define TAO_IDL_HAS_MAP 0
+#endif
+
+#ifndef TAO_IDL_HAS_BITSET
+#  define TAO_IDL_HAS_BITSET 0
+#endif
+
+#ifndef TAO_IDL_HAS_BITMASK
+#  define TAO_IDL_HAS_BITMASK 0
+#endif
+
+#endif
diff --git a/TAO/tao/orbconf.h b/TAO/tao/orbconf.h
index de5905aea50..7559a8b8e14 100644
--- a/TAO/tao/orbconf.h
+++ b/TAO/tao/orbconf.h
@@ -857,6 +857,10 @@ enum TAO_Policy_Scope
 # define TAO_DEFAULT_COLLOCATION_STRATEGY TAO_COLLOCATION_THRU_POA
 #endif
 
+#ifndef TAO_HAS_IDL_FEATURES
+#  define TAO_HAS_IDL_FEATURES 1
+#endif
+
 TAO_END_VERSIONED_NAMESPACE_DECL
 
 #include /**/ "ace/post.h"
diff --git a/TAO/tao/tao.mpc b/TAO/tao/tao.mpc
index 64f85080969..14f122ee9d7 100644
--- a/TAO/tao/tao.mpc
+++ b/TAO/tao/tao.mpc
@@ -448,6 +448,7 @@ project(TAO) : acelib, install, tao_output, taodefaults, pidl, extra_core, taoid
     HTTP_Client.h
     HTTP_Handler.h
     HTTP_Parser.h
+    idl_features.h
     IFR_Client_Adapter.h
     IIOP_Acceptor.h
     IIOPC.h