mkdir wont chmod to 0777

I can get it to chmod to 0755 by leaving the 2nd parameter out of mkdir()

but if i do mkdir($dir,0777) it wont chmod it to 0777

Why is this?

Hello all, ive done quite a bit of searching and found this thread

to solve the problems And this has resolved my problem!

UMASK is what i needed to use, but i dont like simple answers, i wanna know why.

What exactly does umask have to do with getting a directory to be able to be chmod'd to 0777

Thanks!