FERROR(3) BSD Library Functions Manual FERROR(3)
NAME
clearerr, clearerr_unlocked, feof, feof_unlocked, ferror, ferror_unlocked, fileno, fileno_unlocked --check -check
check and reset stream status
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdio.h>
void
clearerr(FILE *stream);
void
clearerr_unlocked(FILE *stream);
int
feof(FILE *stream);
int
feof_unlocked(FILE *stream);
int
ferror(FILE *stream);
int
ferror_unlocked(FILE *stream);
int
fileno(FILE *stream);
int
fileno_unlocked(FILE *stream);
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 non-zero nonzero
zero if it is set. The end-of-file indicator can only be cleared by the function clearerr().
The function ferror() tests the error indicator for the stream pointed to by stream, returning non-zero
if it is set. The error indicator can only be reset by the clearerr() function.
The function fileno() examines the argument stream and returns its integer descriptor.
The clearerr_unlocked(), feof_unlocked(), ferror_unlocked(), and fileno_unlocked() functions are equiv-alent equivalent
alent to clearerr(), feof(), ferror(), and fileno() respectively, except that the caller is responsible
for locking the stream with flockfile(3) before calling them. These functions may be used to avoid the
overhead of locking the stream and to prevent races when multiple threads are operating on the same
stream.
ERRORS
These functions should not fail and do not set the external variable errno.
SEE ALSO
open(2), fdopen(3), flockfile(3), stdio(3)
STANDARDS
The functions clearerr(), feof(), and ferror() conform to ISO/IEC 9899:1990 (``ISO C90'').
BSD January 10, 2003 BSD
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