nofileerrors/0 resets the fileerrors flag, so that the
built-in predicates that open files simply fail, instead of raising
an exception if the specified file cannot be opened.
To cancel the effect of fileerrors/0, call nofileerrors/0.
It sets the fileerrors
flag to its default state, on, in which an error message is produced by
see/1, tell/1, and open/3 if the specified file
cannot be opened. The error message is followed by an
abort/0; that is, execution of the program is abandoned and the system
returns to top level.
The fileerrors flag is only enabled or disabled by an explicit call to
fileerrors/0 or nofileerrors/0, or via prolog_flag/[2,3],
which can also be
used to obtain the current value of the fileerrors flag. See
ref-lps-ove, for more information on the fileerrors flag.