passing command line arguments to an MFC application

Thanks for the comments. This has been useful. There is another thing that I want to know.

How to debug the application while passing it the arguments. I am using VS .NET 2003. I can debug the application from with in the IDE.

But how to see what is going on in the program when I call it through the command line.

suppose if I type the command STARTLOAD E:\DATA.DAT (STARTLOAD is the program) does the variable m_lpCmdLine contain the string E:\DATA.DAT

when I hardwired the value of m_lpCmdLine to E:\\DATA.DAT it is working fine, the file is loading. but when I type the above line at command prompt I am receiving the message that File cannot be opened. MSDN says that m_lpCmdLine is a pointer to a NULL terminated string. So, does it not contain the value passed after the program name.

can you tell how to debug it.

thanks.

Here is what I am trying to do. I want to keep things as simple as possible.

if(m_lpCmdLine[0]==NULL)
{
        pFrame = new CMainFrame(); // do no specific action other than starting the application normally
}

else                     // indicate that a file has to be loaded. First check whether the file can be opened or not and if so set a flag to load it later
{
      pFrame = new CMainFrame();
      if(!m_object->SetFilePath((CString)m_lpCmdLine))
      {
            MessageBox(NULL, "Unable to Open File", "Error", MB_OK);
      }
      else
      {
            m_object->SetLoadData(true);
      }
}

if I hardwire the value of m_lpCmdLine to the filepath require, like E:\\Data.dat then the application is working fine. But if I type the line STARTLOAD E:\Data.dat
I am receiving the error message "Unable to Open File" which is the Message Box in the first 'if' condition above. What is causing the problem here.

Thanks very much, all of your comments are very useful and I solved my problem using them. Now I can use command line to pass application some arguments and it is working good.

thanks,
Aravind.

If you want to handle the command line arguments yourself, use __argv and __argc instead of argv and argc.

myprog.exe "c:/program files/My company/my app" -foo

then

__argc = 3
__argv[0] = <full path>myprog.exe
__argv[1] = c:/program files/My company/my app
__argv[2] = -foo

Nice and easy...

__argc and __argv are defined in stdlib.h which should get pulled it by other includes. They are defined as different things depending on how you link, but the usage is the same.

But where to handle them inside and SDI MFC application. There will only be callbacks here and there is no main in the program. So, where do they appear. Is it in CWinApp::InitInstance()

They are accessible from anywhere in your program because they are global variables or global functions (depending on how you link), they are not passed in as args to a main function like argc and argv.

You can use them in CWinApp::InitInstance or CMyDialog::OnInitDialog or CFrameWnd::wherever. Typically you would want to process them in your InitInstance() function because that is the first function of yours that gets called, but you can use them anywhere.