The STATUS Argument

Each VAL_ and VEC_ routine takes a standard integer STATUS variable as its final argument. In normal use, this STATUS variable should be set to SAI__OK when the routine is invoked, otherwise it will return immediately without action.³

On exit, the STATUS value will still be set to SAI__OK unless a numerical error has occurred, in which case it will be set to an appropriate error code (Appendix ). PRIMDAT error codes may be tested to detect when a particular numerical error has occurred, and may also be used to report these errors (using the ADAM ERR_ routines for instance).

Note that routines in this package do not report errors themselves. This is partly an efficiency consideration. In many circumstances, the automatic generation of a bad value will itself be an adequate response to a numerical error and, in such cases, the STATUS variable may simply be reset to SAI__OK and processing can continue.