NAME

fclose - close a file

fclose - close a stream

SYNOPSIS

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

#include <stdio.h>

int fclose(FILE *stream);

DESCRIPTION

This function closes a file that has been opened via fopen. It expects as input the pointer to a FILE that was returned by fopen.

The fclose() function flushes the stream pointed to by stream (writing any buffered output data using fflush(3)) and closes the underlying file descriptor.

The behaviour of fclose() is undefined if the stream parameter is an illegal pointer, or is a descriptor already passed to a previous invocation of fclose().

RETURN VALUE

This function returns 0 if successful and EOF, a constant, in cases of error.

Upon successful completion, 0 is returned. Otherwise, EOF is returned and errno is set to indicate the error. In either case, any further access (including another call to fclose()) to the stream results in undefined behavior.

EXAMPLE

#inclue <stdio.h>
int main(void) { FILE *file = fopen("cs50.txt", "w"); if (file != NULL) { fprintf(file, "This is CS50\n"); fclose(file); } }

ERRORS

EBADF

The file descriptor underlying stream is not valid.

The fclose() function may also fail and set errno for any of the errors specified for the routines close(2), write(2), or fflush(3).

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
fclose() Thread safety MT-Safe

CONFORMING TO

POSIX.1-2001, POSIX.1-2008, C89, C99.

NOTES

Note that fclose() flushes only the user-space buffers provided by the C library. To ensure that the data is physically stored on disk the kernel buffers must be flushed too, for example, with sync(2) or fsync(2).

SEE ALSO

close(2), fcloseall(3), fflush(3), fileno(3), fopen(3), setbuf(3)

COLOPHON

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