Add is_version_at_least function

[libs/gl.git] / source / extension.h

diff --git a/source/extension.h b/source/extension.h
index aec516e2766a3bce033f3bbd0e7942e04417c587..ed2530a922fdf5c7ae3de64a29d4de3e693d0d62 100644 (file)
--- a/source/extension.h
+++ b/source/extension.h
@@ -1,7 +1,7 @@
 /* $Id$
 
 This file is part of libmspgl
-Copyright © 2007  Mikko Rasa, Mikkosoft Productions
+Copyright © 2007-2008, 2010  Mikko Rasa, Mikkosoft Productions
 Distributed under the LGPL
 */
 
@@ -27,6 +27,19 @@ functions of that extension are safe to use.
 */
 bool is_supported(const std::string &);
 
+/**
+Checks that an extension is supported and throws if it isn't.
+*/
+void require_extension(const std::string &);
+
+/**
+RAII version of require_extension.  Useful as a static local variable.
+*/
+struct RequireExtension
+{
+       RequireExtension(const std::string &e) { require_extension(e); }
+};
+
 /**
 Returns the OpenGL version number, as reported by the implementation.
 Functions up to the returned version are safe to use.
@@ -34,9 +47,9 @@ Functions up to the returned version are safe to use.
 const Version &get_gl_version();
 
 /**
-Checks that an extension is supported and throws if it isn't.
+Indicates whether the OpenGL version is at least a.b.
 */
-void require_extension(const std::string &);
+bool is_version_at_least(unsigned a, unsigned b);
 
 /**
 Checks that the OpenGL version is at least a.b and throws if it isn't.
@@ -44,7 +57,15 @@ Checks that the OpenGL version is at least a.b and throws if it isn't.
 void require_version(unsigned a, unsigned b);
 
 /**
-Returns the address of an extension function.
+RAII version of require_version.  Useful as a static local variable.
+*/
+struct RequireVersion
+{
+       RequireVersion(unsigned a, unsigned b) { require_version(a, b); }
+};
+
+/**
+Returns the address of an extension function.  Only indended for internal use.
 */
 ExtFunc *get_proc_address(const std::string &);