is set to the current error message unit number.
Note that Fortran unit numbers must be positive or zero. If nerr
, output of error messages is totally suppressed. It is important to note that if you supply an illegal value for nerr
(such as a unit number associated with a file opened for reading instead of writing) then x04aaf
cannot detect that fact, but any output sent to the unit by later calls of NAG routines may have undesirable consequences, such as program crashes.