#include <stdio.h>
int fflush(FILE *stream);
int fclose(FILE *stream);

fflush flushes the buffers of an output stream. This is useful if you want to print out debugging information just before a program is expected to crash; the crash may cause buffered data to be lost.

A stream should be closed after use, ensuring that all data have been properly written. fclose takes a stream, flushes it, and closes it. The FILE * handle is invalid after that point and cannot be used again.

All streams are closed when the program terminates normally.