Add support for the 'Present' extension. [v3]

This makes updating the eyes nicely vblank synchronized.

v2:
	Ensure extensions exist before calling query_version

	These calls add calls to xcb_get_extension_data before calling
	query_version calls, as those calls will mark the connection
	with an error if made against an X server without the
	extension present.

	Suggested-by: Uli Schlachter <psychon@znc.in>

v3:
	check the 'present' field in the return from
	xcb_get_extension_data; the xcb_get_extension_data call will
	always succeed (save for out of memory), the only way to tell
	if the extension is supported in the target X server is to
	test the 'present' field in the query extension reply value.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/Eyes.h b/Eyes.h
index 5170356..6bac782 100644
--- a/Eyes.h
+++ b/Eyes.h
@@ -35,6 +35,8 @@
 #define XtNrender	"render"
 #define XtNdistance	"distance"
 
+#define XtNpresent      "present"
+
 enum EyesPart {
 	PART_CLEAR = -1,