_Taccess () function used for DVD-ROM in WinXP and Win7

I got a problem when using the _taccess () function:

int nAccess = _taccess("x:", 06);

      

        
        
        
      

    

x

is my DVD-ROM. This function returns different results in WinXP and Win7: In WinXP, the function returns -1, which means it is NOT writable. But in Win7, the function returns 0, which indicates writeability.

How does this happen? So what should I do if I want to test a DVD-ROM recording (eg "x:")?