NAME
clearerr,
clearerr_unlocked, feof,
feof_unlocked, ferror,
ferror_unlocked, fileno,
fileno_unlocked —
check and reset stream
status
LIBRARY
library “libc”
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 functionclearerr()
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 if it is set. The
end-of-file indicator may be cleared by explicitly calling
clearerr(), or as a side-effect of other operations,
e.g.
fseek().
The function
ferror()
tests the error indicator for the stream pointed to by
stream, returning non-zero if it is set.
The function
fileno()
examines the argument stream and returns its integer
descriptor.
The
clearerr_unlocked(),
feof_unlocked(),
ferror_unlocked(),
and
fileno_unlocked()
functions are equivalent 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
STANDARDS
The functions clearerr(),
feof(), and ferror() conform
to ISO/IEC 9899:1990
(“ISO C90”).