diff --git a/tools/emulator/opengl/system/GLESv2_enc/gl2.attrib b/tools/emulator/opengl/system/GLESv2_enc/gl2.attrib
index bf266dfc1..e764c10de 100644
--- a/tools/emulator/opengl/system/GLESv2_enc/gl2.attrib
+++ b/tools/emulator/opengl/system/GLESv2_enc/gl2.attrib
@@ -175,6 +175,7 @@ glGetShaderPrecisionFormat
 glGetShaderSource
 	dir length out
 	len length (sizeof(GLsizei))
+	var_flag length nullAllowed
 	dir source out
 	len source bufsize