[PROGRAMMING TIPS] Detecting memory leak (MSVC)

Microsoft provided library CRTDBG to detect memory leak in source code. Here is an example how to detect memory leak using CRTDBG:

      #include <stdio.h>



      #ifdef _DEBUG

      #include <crtdbg.h>

      #include <string.h>

      #include <malloc.h>

      #define  SET_CRT_DEBUG_FIELD(a)                   _CrtSetDbgFlag((a) | _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG))

      #define  CLEAR_CRT_DEBUG_FIELD(a)                   _CrtSetDbgFlag(~(a) & _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG))

      #else

      #define  SET_CRT_DEBUG_FIELD(a)   ((void) 0)

      #define  CLEAR_CRT_DEBUG_FIELD(a) ((void) 0)

      #endif



      int main(int argc, char *argv[])

      {

        // variable

        char *p;



      #ifdef _DEBUG

        _CrtMemState s1, s2, s3;

        _CrtSetReportMode( _CRT_WARN, _CRTDBG_MODE_FILE );

        _CrtSetReportFile( _CRT_WARN, _CRTDBG_FILE_STDOUT );

        _CrtSetReportMode( _CRT_ERROR, _CRTDBG_MODE_FILE );

        _CrtSetReportFile( _CRT_ERROR, _CRTDBG_FILE_STDOUT );

        _CrtSetReportMode( _CRT_ASSERT, _CRTDBG_MODE_FILE );

        _CrtSetReportFile( _CRT_ASSERT, _CRTDBG_FILE_STDOUT );

        _CrtMemCheckpoint( &s1 );

      #endif



        // do some work here

        p = (char *)malloc(sizeof(char)*100);

        strcpy(p,"Hello world");

        printf("%s\n",p);

        //free(p);	// Seolah2 kita lupa mem-free



      #ifdef _DEBUG

        _CrtMemCheckpoint( &s2 );

        if ( _CrtMemDifference( &s3, &s1, &s2 ) ){

          printf("\n------------\nOuups! leak detection.\n");

          _CrtMemDumpStatistics( &s3 );

        }else{

          printf("\n------------\nCongratulation! no leak detection.\n");

        }

      #endif

        return 0;

      } // end of main

Use option /MTd to compile the code, e.g. cl memdetect.c /MTd