[gtk+/wip/ebassi/gles: 15/17] docs: Clarify the platform-dependency of GdkGLContext:use-es

[Emmanuele Bassi <ebassi src gnome org>]

commit 9a867de37ec42d0daf4ca6e87e6384627f769d38
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Sat Apr 23 10:33:08 2016 +0100

    docs: Clarify the platform-dependency of GdkGLContext:use-es
    
    Not all platforms allow creating an OpenGL ES context.

 gdk/gdkglcontext.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/gdk/gdkglcontext.c b/gdk/gdkglcontext.c
index ca29955..4a10536 100644
--- a/gdk/gdkglcontext.c
+++ b/gdk/gdkglcontext.c
@@ -655,13 +655,14 @@ gdk_gl_context_set_is_legacy (GdkGLContext *context,
  * @context: a #GdkGLContext:
  * @use_es: whether the context should use OpenGL ES instead of OpenGL
  *
- * Requests that GDK create a OpenGL ES context instead of an OpenGL one.
+ * Requests that GDK create a OpenGL ES context instead of an OpenGL one,
+ * if the platform and windowing system allows it.
  *
  * The @context must not have been realized.
  *
- * You should check the return value of gdk_gl_context_get_use_es() to
- * decide whether to use the OpenGL or OpenGL ES API, extensions, or
- * shaders.
+ * You should check the return value of gdk_gl_context_get_use_es() after
+ * calling gdk_gl_context_realize() to decide whether to use the OpenGL or
+ * OpenGL ES API, extensions, or shaders.
  *
  * Since: 3.22
  */