fileno (3)

Leading comments

Copyright (c) 1990, 1991 The Regents of the University of California.
All rights reserved.

This code is derived from software contributed to Berkeley by
Chris Torek and the American National Standards Committee X3,
on Information Processing Systems.

%%%LICENSE_START(BSD_4_CLAUSE_UCB)
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above c...

(The comments found at the beginning of the groff file "man3/fileno.3".)

NAME

clearerr, feof, ferror, fileno - check and reset stream status

SYNOPSIS

#include <stdio.h>

void clearerr(FILE *stream);
int feof(FILE *stream);
int ferror(FILE *stream);
int fileno(FILE *stream);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

fileno(): _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_SOURCE

DESCRIPTION

The function clearerr() clears the end-of-file and error indicators for the stream pointed to by stream.

The function feof() tests the end-of-file indicator for the stream pointed to by stream, returning nonzero if it is set. The end-of-file indicator can be cleared only by the function clearerr().

The function ferror() tests the error indicator for the stream pointed to by stream, returning nonzero if it is set. The error indicator can be reset only by the clearerr() function.

The function fileno() examines the argument stream and returns its integer descriptor.

For nonlocking counterparts, see unlocked_stdio(3).

ERRORS

These functions should not fail and do not set the external variable errno. (However, in case fileno() detects that its argument is not a valid stream, it must return -1 and set errno to EBADF.)

ATTRIBUTES

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

Interface	Attribute	Value
clearerr(), feof(), ferror(), fileno()	Thread safety	MT-Safe

CONFORMING TO

The functions clearerr(), feof(), and ferror() conform to C89, C99, POSIX.1-2001, and POSIX.1-2008.
The function fileno() conforms to POSIX.1-2001 and POSIX.1-2008.

SEE ALSO

open(2), fdopen(3), stdio(3), unlocked_stdio(3)

COLOPHON

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