ferror(3) — Linux manual page


FERROR(3)               Linux Programmer's Manual              FERROR(3)

NAME         top

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

SYNOPSIS         top

       #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

       fileno(): _POSIX_C_SOURCE

DESCRIPTION         top

       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

       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
       the integer file descriptor used to implement this stream.  The
       file descriptor is still owned by stream and will be closed when
       fclose(3) is called.  Duplicate the file descriptor with dup(2)
       before passing it to code that might close it.

       For nonlocking counterparts, see unlocked_stdio(3).

ERRORS         top

       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         top

       For an explanation of the terms used in this section, see

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

CONFORMING TO         top

       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         top

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

COLOPHON         top

       This page is part of release 5.10 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

                               2019-03-06                      FERROR(3)

Pages that refer to this page: fsync(2)fclose(3)fflush(3)fgetc(3)fmemopen(3)fopen(3)fread(3)fseek(3)gets(3)getw(3)open_memstream(3)pcap_file(3pcap)puts(3)scanf(3)stdio(3)