4.4 fclose—close a file

Synopsis

#include <stdio.h>
int fclose(FILE *fp);
int _fclose_r(struct _reent *reent, FILE *fp);

Description
If the file or stream identified by fp is open, fclose closes it, after first ensuring that any pending data is written (by calling fflush(fp)).

The alternate function _fclose_r is a reentrant version. The extra argument reent is a pointer to a reentrancy structure.

Returns
fclose returns 0 if successful (including when fp is NULL or not an open file); otherwise, it returns EOF.

Portability
fclose is required by ANSI C.

Required OS subroutines: close, fstat, isatty, lseek, read, sbrk, write.