-GLsync_ = Opaque("GLsync")
-GLsync = Handle("sync", GLsync_)
+# GL mappings are pointers to linear memory regions.
+#
+# The map length is not always available in the function prototype, and must be
+# reconstructed from other state.
+GLmap = LinearPointer(GLvoid, "length")
+
+GLsync = Handle("sync", IntPointer("GLsync"))