set verify;

create module LIB_ROUTINES
    language SQL

    procedure LIB$GETJPI
        (in :item_code integer by reference
        ,inout :process_id integer by reference
        ,in :process_name integer by value
        ,out :resultant_value integer);
    external
        name LIB$GETJPI
        location 'SYS$SHARE:LIBRTL.EXE'
        language GENERAL
        GENERAL parameter style
        bind on client site
        comment is
            'LIB$GETJPI'
        /   '--'
        /   'The Get Job/Process Information routine provides a'
        /   'simplified interface to the $GETJPI system service. '
        /   'It provides accounting, status, and identification'
        /   'information about a specified process.'
        /   'LIB$GETJPI obtains only one item of information'
        /   'in a single call.';

    function CURRENT_PID
    returns integer
    comment is 'A jacket function to return the results from LIB$GETJPI';
    begin
    declare :JPI$_PID constant integer = 793;
    declare :in_pid, :out_pid integer;
    call LIB$GETJPI (:JPI$_PID, :in_pid, 0, :out_pid);
    return :out_pid;
    end;

end module;

-- The function is now used as shown
select CURRENT_PID () from rdb$database;