Inserting

are there any open/write functions for C , which do not overwrite chars in a file , but insert them ?

or do i have to write a shitty loop that just reads , stores and writes a char ?

also discuss file and string handling libraries because most that i have seen suck .

No, there aren't. You'll have to use your shitty loop, although you can make it QUITE a bit less shitty (in terms of performance) by reading/writing large blocks instead.

What exactly is sucking about the I/O ("file handling") routines in C?