Returns a nonzero integer if an error occurred while reading or
    writing a file.

    Format

      #include  <stdio.h>

      int ferror  (FILE *file_ptr);

1 - Argument

 file_ptr

    A file pointer.

2 - Description

    A call to ferror continues to return a nonzero integer until the
    file is closed or until clearerr is called.

3 - Return Values

    0                  Indicates success.
    nonzero integer    Indicates that an error has occurred.