The subroutines do things like opening, closing, creating and deleting HDS objects (see SUN/92) but instead of passing the object name to the subroutine, the name of a program parameter is passed. The parameter system then associates the parameter with the required object, using the normal parameter system process, involving the Interface Module (see SUN/115) and possibly prompting the user.
Apart from DAT_CANCL, all the routines obey the Starlink error-handling convention described in SUN/104 - if the STATUS argument is not SAI__OK on entry, they return without action; if they detect an error, they report an error message and return an appropriate STATUS value. DAT_CANCL will attempt to operate regardless of the given status value.
HDSPAR - HDS Parameter Routines