[Spice-devel] [vdagent-win PATCH v6] vdagent: Add a comment around WinSta0_DesktopSwitch event usage

[Frediano Ziglio]

Multiple times while I was reading this code was not clear why the
synchronization of this event was not done in the main event loop.
Also document why we want to use it not relying just on
WTSRegisterSessionNotification and WM_WTSSESSION_CHANGE.

Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
---
 vdagent/vdagent.cpp | 5 +++++
 1 file changed, 5 insertions(+)

Changes since previous version:
- fixed some typos.

diff --git a/vdagent/vdagent.cpp b/vdagent/vdagent.cpp
index f3d60c7..89019bb 100644
--- a/vdagent/vdagent.cpp
+++ b/vdagent/vdagent.cpp
@@ -229,6 +229,11 @@ VDAgent::~VDAgent()
 DWORD WINAPI VDAgent::event_thread_proc(LPVOID param)
 {
     VDAgent *agent = static_cast<VDAgent *>(param);
+    // This event is monitored in a separate thread to avoid losing
+    // events as the event is signaled with PulseEvent to wake up all
+    // thread waiting for it.
+    // This event allows to detect desktop switches which do not
+    // change sessions like pressing Ctrl-Alt-Delete.
     HANDLE desktop_event = OpenEvent(SYNCHRONIZE, FALSE, L"WinSta0_DesktopSwitch");
     if (!desktop_event) {
         vd_printf("OpenEvent() failed: %lu", GetLastError());
-- 
2.17.1