C/C++ system使用的若干坑

1、在实战项目中 system在Windows下类似于向dos发送命令作用

2、在MFC下面 CFileDialg使用之后，IO访问层面的当前路径就会被修改，使用相对路径会受到影响

3、管道技术：在跨进程间的通讯是个不错的方法。以本次项目为例；Exe发送dos命令

//管??道???命??令??

void Pipe ( char * strExe , char * szArgman , CString & strOuter )

{

        CString   strCmdLine( "" );  

       strCmdLine. Format ( "%s %s" , strExe, szArgman);  //strCmd = "ipconfig.exe" 

        //创???建??管??道??? 

        HANDLE                    hReadPipe;   

        HANDLE                    hWritePipe; 

        SECURITY_ATTRIBUTES       sat;                            //安?2全??属??性?结??构1 

       sat. nLength                  = sizeof ( SECURITY_ATTRIBUTES );  //结??构1体??大???小? 

       sat. bInheritHandle          = true ;                         //指?出?安?2全??描??述??符??的??对?象??能??否??被??新?进?程??继??承D 

       sat. lpSecurityDescriptor = NULL ;                         //安?2全??描??述??符??,NULL: 使?1用??默?认??的??  

        if ( ! CreatePipe ( &hReadPipe, &hWritePipe, &sat, NULL ) )   

       {   

              strOuter = _T ( "Create Pipe Error!" );

               return ;    

       } 

        //创???建??进?程?? 

        STARTUPINFO                  startupinfo;             //进?程??信?息?? 

        PROCESS_INFORMATION    pinfo; 

       startupinfo. cb                  = sizeof ( STARTUPINFO ); //结??构1体??大???小?  

        GetStartupInfo ( &startupinfo );                  //获?取??当???前??进?程??的??信?息?? 

       startupinfo. hStdError         = hWritePipe;   

       startupinfo. hStdOutput      = hWritePipe;   

       startupinfo. dwFlags           = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES ;   

       startupinfo. wShowWindow = SW_HIDE ;     

        if ( ! CreateProcess ( NULL , strCmdLine. GetBuffer (0), NULL , NULL , 

               TRUE , NULL , NULL , NULL , &startupinfo, &pinfo) )   

       {    

              strOuter = _T ( "CreateProcess " ); 

               return ;    

       }   

        CloseHandle ( hWritePipe );  

        //获?取??管??道???信?息?? 

        BYTE        buffer [1024]; 

        DWORD     byteRead; 

        while ( true )   

       {   

               RtlZeroMemory ( buffer , 1024 );  

               if ( ReadFile ( hReadPipe, buffer , 1023, &byteRead, NULL ) == NULL ) 

              {   printf ( "%s" , buffer );

                      break ;    

              }

               printf ( "\r\n" );

         strOuter = buffer ;

       }   

        CloseHandle ( hReadPipe );  

       strCmdLine. ReleaseBuffer (); 

}

4、调整IO对应的根目录

    #include <stdlib.h>

    #include <direct.h>

    _chdir(char szPath);    //  设置IO的当前路径