fclose, fflush - close or flush a stream
int fclose(FILE *stream)
int fflush(FILE *stream)
Fclose causes any buffers for the named stream to be emptied, and the
file to be closed. Buffers allocated by the standard input/output system
Fclose is performed automatically upon calling exit(3).
Fflush causes any buffered data for the named output stream to be written
to that file. The stream remains open.
close(2), fopen(3), setbuf(3).
These routines return EOF if stream is not associated with an output
file, or if buffered data cannot be transferred to that file.