Question

I use CreateFile to initially create a file, with:

HANDLE hFile = CreateFile (TEXT(fileName.str().c_str()),      
                  GENERIC_WRITE,          
                  0,                     
                  NULL,                   
                  OPEN_ALWAYS,            
                  FILE_ATTRIBUTE_NORMAL,  
                  NULL);             

If I use CreateFile again to try and create the same file again, should it not be an error?

hFile = CreateFile (TEXT(fileName.str().c_str()),      
                  GENERIC_WRITE,          
                  0,                      
                  NULL,                   
                  CREATE_ALWAYS,             
                  FILE_ATTRIBUTE_NORMAL,  
                  NULL);              

I would have thought because I use CREATE_ALWAYS that it fails if the file is already created.

Answer 1

No, CREATE_ALWAYS flag makes CreateFile to overwrite the file if it already exists. You should use CREATE_NEW to achieve what you want.