Output debug information to the console or file

Output debug information to the console or file

We often encounter this situation. The planners ran to say that the program had gone wrong, and then gave a great description of the program without making the problem clear. If the program running information can be automatically recorded, it is much easier to find bugs, that is, the log function.

In addition, for debugging programs, you often need to input some debugging information in the program, so that you can more easily find bugs. The debugging information can only be seen in the debugging mode of the editor, or by using third-party software such as debugview, but it is restricted by the compiling environment, and it is impossible to run the program with debugview every time... It is much easier to automatically record debugging information to log files.

In debugging mode, the debugger obtains information because it captures the output information of outputdebugstring () in the program. Therefore, if we can write a program to capture the output information of the outputdebugstring () function, we can solve the above requirements. For the principle of the outputdebugstring () function, refer to http://www.unixwiz.net/techtips/outputdebugstring.html.

After understanding the principles, it is easy to implement them. The code below is as follows:

1 const max_debugbuffer = 4096; // the data transmitted between the application and the debugger is completed through a 4 kb shared memory block.
2
3 typedef struct dbwin_buffer {
4 DWORD dwprocessid;
5 char data [4096-sizeof (DWORD)];
6} debugbuffer, * pdebugbuffer;
7
8 // thread Functions
9 void winapi debugtrackproc (pvoid pvparam)
10 {
11 handle hmapping = NULL;
12 handle hackevent = NULL;
13 handle hreadyevent = NULL;
14 pdebugbuffer pdbbuffer = NULL;
15 tchar tzbuffer [max_debugbuffer];
16
17 // open the event handle
18 hackevent = createevent (null, false, false, text ("dbwin_buffer_ready "));
19 if (hackevent = NULL)
20 {
21 closehandle (hackevent );
22 return;
23}
24
25 hreadyevent = createevent (null, false, false, text ("dbwin_data_ready "));
26 if (hreadyevent = NULL)
27 {
28 closehandle (hreadyevent );
29 return;
30}
31
32 // Create File ing
33 hmapping = createfilemapping (invalid_handle_value, null, page_readwrite, 0, max_debugbuffer, text ("dbwin_buffer "));
34 if (hmapping = NULL)
35 {
36 closehandle (hmapping );
37 return;
38}
39
40 // map the debugging Buffer
41 pdbbuffer = (pdebugbuffer) mapviewoffile (hmapping, file_map_read, 0, 0, 0 );
42
43 // Loop
44 While (true)
45 {
46 // activate the event
47 setevent (hackevent );
48 // wait for the buffer data
49 If (waitforsingleobject (m_hreadyevent, infinite) = wait_object_0)
50 {
51 // Save the information. This is what we want. With this information, you can log it or output it to the console.
52 tzbuffer = pdbbuffer-> szstring;
53}
54}
55
56 // release
57 if (pdbbuffer)
58 {
59 unmapviewoffile (pdbbuffer );
60}
61 closehandle (hmapping );
62 closehandle (hreadyevent );
63 closehandle (hackevent );
64}

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