[PATCH libXi] XIChangeHierarchy: Return Success early if no actual changes are requested.

[Peter Hutterer]

Do the same for negative num_changes.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 man/XIChangeHierarchy.txt |    3 ++-
 src/XIHierarchy.c         |    3 +++
 2 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/man/XIChangeHierarchy.txt b/man/XIChangeHierarchy.txt
index ac667bc..205f40f 100644
--- a/man/XIChangeHierarchy.txt
+++ b/man/XIChangeHierarchy.txt
@@ -30,7 +30,8 @@ DESCRIPTION
    XIChangeHierarchy modifies the device hierarchy by creating or
    removing master devices or changing the attachment of slave
    devices. If num_changes is non-zero, changes is an array of
-   XIAnyHierarchyChangeInfo structures.
+   XIAnyHierarchyChangeInfo structures. If num_changes is equal or less than
+   zero, XIChangeHierarchy does nothing.
 
    XIChangeHierarchy processes changes in order, effective
    immediately. If an error occurs, processing is aborted and the
diff --git a/src/XIHierarchy.c b/src/XIHierarchy.c
index d30ea29..09e6f93 100644
--- a/src/XIHierarchy.c
+++ b/src/XIHierarchy.c
@@ -52,6 +52,9 @@ XIChangeHierarchy(Display* dpy,
     if (_XiCheckExtInit(dpy, XInput_2_0, info) == -1)
 	return (NoSuchExtension);
 
+    if (num_changes <= 0)
+        return Success;
+
     GetReq(XIChangeHierarchy, req);
     req->reqType = info->codes->major_opcode;
     req->ReqType = X_XIChangeHierarchy;
-- 
1.7.4.4