Mesa (master): mesa: Add a clarifying comment about EXTRA_ error checking.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 072709da91d403fc9ee69b3a9d4978ae7b24549a
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=072709da91d403fc9ee69b3a9d4978ae7b24549a

Author: Eric Anholt <eric at anholt.net>
Date:   Wed Apr 10 09:59:41 2013 -0700

mesa: Add a clarifying comment about EXTRA_ error checking.

---

 src/mesa/main/get.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index 73ad8fe..adb7bd2 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -226,7 +226,13 @@ union value {
  * extensions or specific gl versions) or actions (flush current, new
  * buffers) that we need to do before looking up an enum.  We need to
  * declare them all up front so we can refer to them in the value_desc
- * structs below. */
+ * structs below.
+ *
+ * Each EXTRA_ will be executed.  For EXTRA_* enums of extensions and API
+ * versions, listing multiple ones in an array means an error will be thrown
+ * only if none of them are available.  If you need to check for "AND"
+ * behavior, you would need to make a custom EXTRA_ enum.
+ */
 
 static const int extra_new_buffers[] = {
    EXTRA_NEW_BUFFERS,