VMS Help SCA, SCA Topics, Callable Routines, SCA$QUERY_INITIALIZE, Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 command_context
    type:       $SCA_COMMAND_CONTEXT
    access:     read/write
    mechanism:  by reference

    An SCA command context.

 query_context
    type:       $SCA_QUERY_CONTEXT
    access:     write only
    mechanism:  by reference

    An SCA query context to be initialized. This value is passed as an
    argument to other SCA query routines (SCA$QUERY_xxx).