Question

what's the function of fflush in c?

Answer 1

The C library function int fflush(FILE *stream) flushes the output buffer of a stream.

Answer 2

What do you need to know about it? Here is a good example

http://www.tutorialspoint.com/c_standard_library/c_function_fflush.htm

Answer 3

Just never use it on an unput buffer:
http://faq.cprogramming.com/cgi-bin/smartfaq.cgi?answer=1052863818&id=1043284351

Answer 4

Or input buffer... it is an output flush, so undefined for input.