NAME

       clearerr, feof, ferror - check and reset stream status

LIBRARY

       Standard C library (libc, -lc)

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 │
       └──────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       C11, POSIX.1-2008.

HISTORY

       C89, POSIX.1-2001.

NOTES

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

CAVEATS

       Normally,  programs  should  read  the  return value of an input function, such as fgetc(3), before using
       functions of the feof(3) family.  Only when the function returned the sentinel value EOF it  makes  sense
       to distinguish between the end of a file or an error with feof(3) or ferror(3).

SEE ALSO

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