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

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

SYNOPSIS
       #include <stdio.h>

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

       For nonlocking counterparts, see unlocked_stdio(3).

RETURN VALUE
       The feof() function returns nonzero if the end-of-file indicator is set for stream; otherwise, it returns zero.

       The ferror() function returns nonzero if the error indicator is set for stream; otherwise, it returns zero.

ERRORS
       These functions should not fail and do not set errno.

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

       ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                                                                                             │ Attribute     │ Value   │
       ├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │clearerr(), feof(), ferror()                                                                                                          │ Thread safety │ MT-Safe │
       └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO
       The functions clearerr(), feof(), and ferror() conform to C89, C99, POSIX.1-2001, and POSIX.1-2008.

NOTES
       POSIX.1-2008 specifies that these functions shall not change the value of errno if stream is valid.

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

                                                                               2021-03-22                                                                      FERROR(3)