It has always struck me as strange that the C function "fopen" takes a "const char *" as the second argument. I would think it would be easier to both read your code and implement the library's code if there were bit masks defined in stdio.h, like "IO_READ" and such, so you could do things like:

FILE* myFile = fopen("file.txt", IO_READ & IO_WRITE);

Is there a programmatic reason for the way it actually is, or is it just historic? (i.e. "That's just the way it is.")