Same as feof, except used only within a scope protected by
    flockfile and funlockfile.

    This function is supported on OpenVMS Integrity servers and
    Alpha only.

    Format

      #include  <stdio.h>

      int feof_unlocked  (FILE *file_ptr);

1 - Argument

 file_ptr

    A file pointer.

2 - Description

    The reentrant version of the feof function is locked against
    multiple threads calling it simultaneously. This incurs overhead
    to ensure integrity of the stream. The unlocked version of this
    call, feof_unlocked can be used to avoid the overhead. The feof_
    unlocked function is functionally identical to the feof function,
    except that it is not required to be implemented in a thread-
    safe manner. The feof_unlocked function can be safely used only
    within a scope that is protected by the flockfile and funlockfile
    functions used as a pair. The caller must ensure that the stream
    is locked before feof_unlocked is used.

    See also flockfile, ftrylockfile, and funlockfile.

3 - Return Values

    nonzero integer    Indicates end-of-file has been reached.
    0                  Indicates end-of-file has not been reached.