03-14-2010
Quote:
Originally Posted by
jlliagre
While I would mostly agree with the file descriptor definition, a file pointer is not usually what you describe but commonly used to refer to what the standard C library uses to handle files (FILE *).
The associated functions are fopen, fclose, fread, fwrite, fscanf and the likes.
I would also note that a file pointer has an associated file descriptor used by the library functions to do the actual I/O calls to the kernel. You can get the associated fd using the fileno function.
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FCLOSE(3) Linux Programmer's Manual FCLOSE(3)
NAME
fclose - close a stream
SYNOPSIS
#include <stdio.h>
int fclose(FILE *stream);
DESCRIPTION
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 invo-
cation of fclose().
RETURN VALUE
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.
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
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
GNU
2016-12-12 FCLOSE(3)