SendMessageTimeout
The SendMessageTimeout
function sends the specified message to a window or windows. The function calls
the window procedure for the specified window and, if the specified window
belongs to a different thread, does not return until the window procedure has
processed the message or the specified time-out period has elapsed. If the
window receiving the message belongs to the same queue as the current thread,
the window procedure is called directly the time-out value is ignored.
LRESULT SendMessageTimeout(
|
HWND hWnd, |
// handle of
destination window |
|
UINT Msg, |
// message to send |
|
WPARAM wParam, |
// first message
parameter |
|
LPARAM lParam, |
// second message
parameter |
|
UINT fuFlags, |
// how to send the
message |
|
UINT uTimeout, |
// time-out
duration |
|
LPDWORD lpdwResult |
// return value for
synchronous call |
|
); |
|
Parameters
hWnd
Identifies
the window whose window procedure will receive the message. If this parameter
is HWND_TOPMOST, the message is sent to all top-level windows in the system,
including disabled or invisible unowned windows.
Msg
Specifies the
message to be sent.
wParam
Specifies
additional message-specific information.
lParam
Specifies
additional message-specific information.
fuFlags
Specifies how
to send the message. This parameter can be a combination of the following
values:
|
Value |
Meaning |
|
SMTO_ABORTIFHUNG |
Returns
without waiting for the time-out period to elapse if the receiving process
appears to be in a hung state. |
|
SMTO_BLOCK |
Prevents
the calling thread from processing any other requests until the function
returns. |
|
SMTO_NORMAL |
The calling
thread is not prevented from processing other requests while waiting for the
function to return. |
uTimeout
Specifies the
duration, in milliseconds, of the time-out period.
lpdwResult
Specifies the
result of the message processing and depends on the message sent.
Return Values
If the
function succeeds, the return value is TRUE.
If the
function fails, the return value is FALSE. To get extended error information,
call GetLastError.
See Also