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C28604

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warning C28604: Avoid calling SendMessageTimeout with SMTO_ABORTIFHUNG with a timeout of 0

The Code Analysis tool reports this warning when applications call SendMessageTimeout with the SMTO_ABORTIFHUNG flag and a time-out period of zero. Using SendMessageTimeout this way can be problematic because the time-out period has no effect, and the call is treated as a blocking call.

Specify a nonzero value for time-out period.

Example

The following function call can cause the process to not respond indefinitely.

fNeedsCallbackEvent = (0 != SendMessageTimeout(
_hwnd, 
WM_NULL, 
0,
0, 
SMTO_ABORTIFHUNG,
0,
&dwResult));

The following function call does not have this problem.

fNeedsCallbackEvent = (0 != SendMessageTimeout(
_hwnd, 
WM_NULL, 
0,
0,
SMTO_ABORTIFHUNG,
1000,  
&dwResult));