First of all, i like PHP verry much.
It's an easy to learn and very usefull language.
Still i have a little problem.

I open a file with fopen() and i read in it with fread().
Then i set the filepointer with fseek() and i verify that
action with ftell().
So far all goes well.
But when i write to the file with fwrite(), i find that
the bytes i wrote are always appended to the file and not
written somewhere in the middle, at the position that i
placed the filepointer on.

So if i have a file with, let's say, 20 bytes (0 - 19),
and i position the filepointer at byte 10, then i should be
able to write in the middle of the file, right?
This doesn't happen.

And how can i truncate an opened file to a specific length?
I want to truncate this file with 20 bytes to a length of
14 bytes. How can i do this?