Notifications for using settimer in the console

Settimer is used to set the timer and execute an operation at intervals. The prototype is as follows:

 

Uint_ptr settimer (

Hwnd, // window handle

Uint_ptr nidevent, // timer ID. When multiple timers exist, you can use this ID to determine which timer is used.

Uint uelapse, // time interval, in milliseconds

Timerproc lptimerfunc // callback function

 

);

 

It triggers the callback function by distributing the wm_timer message. See the following code:

 

[CPP]View plaincopy

1. Void callback timerproc (hwnd, uint nmsg, uint ntimerid, DWORD dwtime)
2. {
3. Printf ("% s", "ABC ");
5. }
6. Void main ()
7. {
8. Settimer (0, 0, 1000, & timerproc );
9. }

 

 

Do you think the above Code will be correctly executed? The answer is no. The callback function cannot be executed at all. Although settimer is used, wm_timer messages are not distributed, so the callback function is not triggered.

 

[CPP]View plaincopy

1. Void callback timerproc (hwnd, uint nmsg, uint ntimerid, DWORD dwtime)
2. {
3. Printf ("% s", "ABC ");
5. }
6. Void main ()
7. {
8. Settimer (0, 0, 1000, & timerproc );
9. MSG;
10. While (getmessage (& MSG, null, 0, 0 ))
11. {
12. If (msg. Message = wm_timer)
13. {
14. Dispatchmessage (& MSG );
15. }
16. }
17. }

 

OK. Do you see the WHILE LOOP above? Here we get the wm_timer message sent every second and distribute it to notify the callback function to start execution.

Reference: http://blog.csdn.net/bdmh/article/details/6371443

Tested and feasible, complete code:

#include "stdafx.h"#include "windows.h"#include "stdio.h"void CALLBACK TimerProc(HWND hWnd,UINT nMsg,UINT nTimerid,DWORD dwTime){  printf("%s","abc");   }void main(){    SetTimer(0, 0, 1000, &TimerProc);    MSG   msg;       while(GetMessage(&msg,NULL,0,0))       {           if(msg.message==WM_TIMER)           {               DispatchMessage(&msg);           }       }   }

Write the following statement:

MSG msg;GetMessage(&msg, NULL, 0, 0);

In this way, the message queue is available, but no one can send messages separately, so the timerproc content will not be executed.

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Notifications for using settimer in the console