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PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface
may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface
may not be implemented on Linux.
NAME
fclose — close a stream
SYNOPSIS
#include <stdio.h>
int fclose(FILE *stream);
DESCRIPTION
The functionality described on this reference page is aligned with the ISO C standard. Any conflict
between the requirements described here and the ISO C standard is unintentional. This volume of
POSIX.1‐2008 defers to the ISO C standard.
The fclose() function shall cause the stream pointed to by stream to be flushed and the associated file
to be closed. Any unwritten buffered data for the stream shall be written to the file; any unread
buffered data shall be discarded. Whether or not the call succeeds, the stream shall be disassociated
from the file and any buffer set by the setbuf() or setvbuf() function shall be disassociated from the
stream. If the associated buffer was automatically allocated, it shall be deallocated.
If the file is not already at EOF, and the file is one capable of seeking, the file offset of the
underlying open file description shall be set to the file position of the stream if the stream is the
active handle to the underlying file description.
The fclose() function shall mark for update the last data modification and last file status change
timestamps of the underlying file, if the stream was writable, and if buffered data remains that has not
yet been written to the file. The fclose() function shall perform the equivalent of a close() on the file
descriptor that is associated with the stream pointed to by stream.
After the call to fclose(), any use of stream results in undefined behavior.
RETURN VALUE
Upon successful completion, fclose() shall return 0; otherwise, it shall return EOF and set errno to
indicate the error.
ERRORS
The fclose() function shall fail if:
EAGAIN The O_NONBLOCK flag is set for the file descriptor underlying stream and the thread would be
delayed in the write operation.
EBADF The file descriptor underlying stream is not valid.
EFBIG An attempt was made to write a file that exceeds the maximum file size.
EFBIG An attempt was made to write a file that exceeds the file size limit of the process.
EFBIG The file is a regular file and an attempt was made to write at or beyond the offset maximum
associated with the corresponding stream.
EINTR The fclose() function was interrupted by a signal.
EIO The process is a member of a background process group attempting to write to its controlling
terminal, TOSTOP is set, the calling thread is not blocking SIGTTOU, the process is not ignoring
SIGTTOU, and the process group of the process is orphaned. This error may also be returned under
implementation-defined conditions.
ENOMEM The underlying stream was created by open_memstream() or open_wmemstream() and insufficient memory
is available.
ENOSPC There was no free space remaining on the device containing the file or in the buffer used by the
fmemopen() function.
EPIPE An attempt is made to write to a pipe or FIFO that is not open for reading by any process. A
SIGPIPE signal shall also be sent to the thread.
The fclose() function may fail if:
ENXIO A request was made of a nonexistent device, or the request was outside the capabilities of the
device.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
Section 2.5, Standard I/O Streams, close(), fmemopen(), fopen(), getrlimit(), open_memstream(), ulimit()
The Base Definitions volume of POSIX.1‐2008, <stdio.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event
of any discrepancy between this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at
http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are most likely to have been introduced
during the conversion of the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 FCLOSE(3POSIX)