FERROR(3)                           Linux Programmer's Manual                           FERROR(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
   Multithreading (see pthreads(7))
       The clearerr(), feof(), ferror(), and fileno() functions are thread-safe.

CONFORMING TO
       The functions clearerr(), feof(), and ferror() conform to C89 and C99.

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

COLOPHON
       This page is part of release 3.53 of the Linux man-pages project.  A  description  of  the
       project,     and    information    about    reporting    bugs,    can    be    found    at
       http://www.kernel.org/doc/man-pages/.



                                            2013-06-21                                  FERROR(3)