Thread-safe Logger with Automatic Removing Log Messages from Release Version

Vlad Kirienko

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13 Sep 2000

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A log file class for multi-threaded applications

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Introduction

This class makes it possible to use log file in multi-threaded applications and has several useful features widely used in my multi-threaded, time sensitive projects where Visual C++ integrated debugger has very limited usage.

CDebugPrintf class provides some useful features:

Thread-safe logging in multi-threaded applications.
Automatic removing log messages from release version of your application.
You don't need anymore to remove or comment log messages in release version. Release version will not have any overhead or unused information in executable file.
You can write log messages at the same time to same file from different applications.
It is useful when it is necessary to explore interaction and timing issues between two or more applications.
Using printfs style for format text: %s, %d, %4.1d, etc.
Sorry, but there is no floating point support.
Data and time stamps for each message in log file.
Also, this class provides time difference stamp from application start.
Console output and easy logging for error codes returned by GetLastError function.
Saving old log files.
Uses only Windows API functions. So it can be used even in non-MFC applications.

The class is easy to use.

Include files dbg.h and dbg.cpp to your project.
At any time you want to write something to the log file, use the PRINTF macro.

Example of Log File Output

0.000 08/25/2000 15:04:48  User name = KVA
0.015 08/25/2000 15:04:48  ISAPI = "TraxDataMgr.dll"
0.015 08/25/2000 15:04:48  CActionHandler constructor
0.015 08/25/2000 15:04:48  CDataMgrActionHandler constructor
5.123 08/25/2000 15:04:53  0   HttpExtensionProc: started
5.123 08/25/2000 15:04:53  Execute request 1 started.   
5.672 08/25/2000 15:04:53  CIndexer constructor: done
5.693 08/25/2000 15:04:53  Open:  D:\Data\Docs\customer
5.693 08/25/2000 15:04:53  Loading index table from 'D:\Data\Docs\customer.idx'
5.693 08/25/2000 15:04:53  Count: 93560
6.132 08/25/2000 15:04:54  Index loading finished ... OK
6.375 08/25/2000 15:04:54  Execute request 1 finished.   
6.375 08/25/2000 15:04:54  0   HttpExtensionProc: finished

Class Usage

C++

void SomeFunction( char* arg1, int arg2, string& arg3 )
{
    // doing something
    ...
    PRINTF("Something happened by using %s and %d arguments", arg1, arg2);
    ...
    // doing something
    ...
    PRINTF(arg3);
    ...
    SHOW_CONSOLE();
    PRINTF("This message is visible on console and in log-file.");
}

Remarks

All log messages must fit into one line of source code because of problem with transparent removing log messages from release version.

C++

PRINTF("One line messages are supported.");

C++

PRINTF("Multi-line messages %s %s",
           "are not",
           "supported.");

License

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A list of licenses authors might use can be found here.

Written By

Vlad Kirienko

United States

This member has not yet provided a Biography. Assume it's interesting and varied, and probably something to do with programming.

BOOL WINAPI ConsoleCtrlEvent_Handler(DWORD dwCtrlEvent) ///////////////////////////////////////////////////// // See documentation for SetConsoleCtrlHandler() // // // This function handles console window events such as // Ctrl+C -- which by default will call ExitProcess() (and your app will exit) // // This function ignores the Ctrl+C event so that your program isn't closed. { switch(dwCtrlEvent) { case CTRL_C_EVENT: //The console window had the reveived the Ctrl+C event //I don't want this to kill my app //so I just return TRUE so that windows will consider //this event handled. return TRUE;//<-- this console event has been handled case CTRL_BREAK_EVENT: //let the default handlers get called case CTRL_CLOSE_EVENT: //for these console events case CTRL_LOGOFF_EVENT: case CTRL_SHUTDOWN_EVENT: default: return FALSE;//<-- call the next console event handler } }

HWND GetConsoleHwnd() { #define MY_BUFSIZE 1024 // buffer size for console window titles HWND hwndFound; // this is what is returned to the caller TCHAR pszNewWindowTitle[MY_BUFSIZE]; // contains fabricated WindowTitle TCHAR pszOldWindowTitle[MY_BUFSIZE]; // contains original WindowTitle // fetch current window title GetConsoleTitle(pszOldWindowTitle, MY_BUFSIZE); // format a "unique" NewWindowTitle _stprintf(pszNewWindowTitle,_T("%d/%d"), GetTickCount(), GetCurrentProcessId()); // change current window title SetConsoleTitle(pszNewWindowTitle); // ensure window title has been updated Sleep(40); // look for NewWindowTitle hwndFound = FindWindow(NULL, pszNewWindowTitle); // restore original window title SetConsoleTitle(pszOldWindowTitle); return(hwndFound); } BOOL DisableConsoleClose() { return RemoveMenu(GetSystemMenu(GetConsoleHwnd(), FALSE), SC_CLOSE, MF_BYCOMMAND); }

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.