fclose.3p (6094B)
- '\" et
- .TH FCLOSE "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
- .\"
- .SH 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.
- .\"
- .SH NAME
- fclose
- \(em close a stream
- .SH SYNOPSIS
- .LP
- .nf
- #include <stdio.h>
- .P
- int fclose(FILE *\fIstream\fP);
- .fi
- .SH 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\(hy2017 defers to the ISO\ C standard.
- .P
- The
- \fIfclose\fR()
- function shall cause the stream pointed to by
- .IR 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
- \fIsetbuf\fR()
- or
- \fIsetvbuf\fR()
- function shall be disassociated from the stream. If the associated
- buffer was automatically allocated, it shall be deallocated.
- .P
- 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.
- .P
- The
- \fIfclose\fR()
- 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
- \fIfclose\fR()
- function shall perform the equivalent of a
- \fIclose\fR()
- on the file descriptor that is associated with the stream pointed to by
- .IR stream .
- .P
- After the call to
- \fIfclose\fR(),
- any use of
- .IR stream
- results in undefined behavior.
- .SH "RETURN VALUE"
- Upon successful completion,
- \fIfclose\fR()
- shall return 0; otherwise, it shall return EOF
- and set
- .IR errno
- to indicate the error.
- .SH ERRORS
- The
- \fIfclose\fR()
- function shall fail if:
- .TP
- .BR EAGAIN
- The O_NONBLOCK flag is set for the file descriptor underlying
- .IR stream
- and the thread would be delayed in the write operation.
- .TP
- .BR EBADF
- The file descriptor underlying stream is not valid.
- .TP
- .BR EFBIG
- An attempt was made to write a file that exceeds the maximum file size.
- .TP
- .BR EFBIG
- An attempt was made to write a file that exceeds the file size
- limit of the process.
- .TP
- .BR 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.
- .TP
- .BR EINTR
- The
- \fIfclose\fR()
- function was interrupted by a signal.
- .TP
- .BR 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.
- .TP
- .BR ENOMEM
- The underlying stream was created by
- \fIopen_memstream\fR()
- or
- \fIopen_wmemstream\fR()
- and insufficient memory is available.
- .TP
- .BR ENOSPC
- There was no free space remaining on the device containing the file or
- in the buffer used by the
- \fIfmemopen\fR()
- function.
- .TP
- .BR 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.
- .P
- The
- \fIfclose\fR()
- function may fail if:
- .TP
- .BR ENXIO
- A request was made of a nonexistent device, or the request was outside
- the capabilities of the device.
- .LP
- .IR "The following sections are informative."
- .SH EXAMPLES
- None.
- .SH "APPLICATION USAGE"
- Since after the call to
- \fIfclose\fR()
- any use of
- .IR stream
- results in undefined behavior,
- \fIfclose\fR()
- should not be used on
- .IR stdin ,
- .IR stdout ,
- or
- .IR stderr
- except immediately before process termination (see the Base Definitions volume of POSIX.1\(hy2017,
- .IR "Section 3.303" ", " "Process Termination"),
- so as to avoid triggering undefined behavior in other standard
- interfaces that rely on these streams. If there are any
- \fIatexit\fR()
- handlers registered by the application, such a call to
- \fIfclose\fR()
- should not occur until the last handler is finishing. Once
- \fIfclose\fR()
- has been used to close
- .IR stdin ,
- .IR stdout ,
- or
- .IR stderr ,
- there is no standard way to reopen any of these streams.
- .P
- Use of
- \fIfreopen\fR()
- to change
- .IR stdin ,
- .IR stdout ,
- or
- .IR stderr
- instead of closing them avoids the danger of a file unexpectedly
- being opened as one of the special file descriptors STDIN_FILENO,
- STDOUT_FILENO, or STDERR_FILENO at a later time in the application.
- .SH RATIONALE
- None.
- .SH "FUTURE DIRECTIONS"
- None.
- .SH "SEE ALSO"
- .IR "Section 2.5" ", " "Standard I/O Streams",
- .IR "\fIatexit\fR\^(\|)",
- .IR "\fIclose\fR\^(\|)",
- .IR "\fIfmemopen\fR\^(\|)",
- .IR "\fIfopen\fR\^(\|)",
- .IR "\fIfreopen\fR\^(\|)",
- .IR "\fIgetrlimit\fR\^(\|)",
- .IR "\fIopen_memstream\fR\^(\|)",
- .IR "\fIulimit\fR\^(\|)"
- .P
- The Base Definitions volume of POSIX.1\(hy2017,
- .IR "\fB<stdio.h>\fP"
- .\"
- .SH COPYRIGHT
- Portions of this text are reprinted and reproduced in electronic form
- from IEEE Std 1003.1-2017, Standard for Information Technology
- -- Portable Operating System Interface (POSIX), The Open Group Base
- Specifications Issue 7, 2018 Edition,
- Copyright (C) 2018 by the Institute of
- Electrical and Electronics Engineers, Inc and The Open Group.
- 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.opengroup.org/unix/online.html .
- .PP
- 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 .