HP C/iX Library Reference Manual (30026-90004)

Chapter 5 141

HP C/iX Library Function Descriptions

fclose

Closes an open ﬁle.

Syntax

#include <stdio.h>

int fclose (FILE *

stream

);

Parameters

stream

A pointer to the ﬁle to be closed.

Return Values

0 The ﬁle is successfully closed.

≠0 An error occurred. The ﬁle is not closed.

Description

The fclose function ﬂushes the buffer associated with the speciﬁed stream, and, if the

buffer was allocated automatically by the standard I/O system, frees the space allocated to

that buffer. The stream is then closed, breaking the connection between your ﬁle pointer

and the stream. The fclose function closes ﬁles opened by the fopen(), fdopen(), or

freopen() functions.

The fclose function takes a pointer to FILE as its argument (returned from a call to

fopen(), fdopen(), or freopen()). The function posts any information written to the ﬁle

that is still in the stream's buffer, and it then closes the ﬁle. This disassociates the ﬁle and

the stream. If the buffer was automatically allocated, it is deallocated.

There are two reasons why you can open a ﬁle, but might never explicitly close the ﬁle.

First, notice that all programs in this chapter that open ﬁles end with a call to exit(). The

exit() call automatically performs an fclose() operation for every open ﬁle in that

program. Second, when a C program is compiled, an exit() call is normally compiled with

your code, so that if you return from main() or reach the } that terminates main(), it is

equivalent to calling exit().