Conference ilbbak::ibi_focus

231.0. "Need help using LIB$ functions in FOCUS!" by WLDWST::RPTTEST () Thu Jun 29 1989 14:29

    Help!!! I am having problems trying to call a RTL procedure from
    a FOCUS callable routine !
    
    I have written two routines, debugged and linked them into FOCUS.
    Both routines use the same parameters, (pass a string in, get a string
    out).                  
    
    The first one takes a Proccess name from our production system
    and turns it into a "Processing Area" identifier and makes my reports
    more organized. It works great. I have used it for 6 months without any
    problems.
    
    The second function passes in a string to search for a CLI symbol using
    the Run-Time Library function "LIB$GET_SYMBOL", and passes the
    resulting string back to FOCUS. When I ran it from a program, it worked
    fine. Without any modification, (except to turn it into an object
    module), running it from FOCUS does not pass anything back. 
    
    I *know* my function is correct because I have not changed anything in
    it from it's program version. I *know* the parameters are being passed
    correctly because it works with the first function. It acts like it is
    linking but not running the library function. I know the symbol I am
    trying to access exists especially because I add a VMS ... statement to
    assign it just before I call my procedure. 
    
    Any Idea on what is going on ? 

						Scott Stephens
						Digital - UCF - Cupertino, CA
						Production Control
                                  
    Below is some of the code I am  writing (PASCAL!)
    
    
[global] module area;

type
   string10 = packed array [1..10] of char;
   string11 = packed array [1..11] of char;
                                                         
    
    (* A matching function which searches for leading sub-strings *)

[global] function starts( in_string : packed array [lo..hi:integer] of char;
                          test_string : varying [len] of char ) 
                        : boolean;
var
   i,j,string_end : integer;
   starting : boolean;
begin
   string_end := length( test_string );
   if string_end > len then string_end := hi;
   starting := true; i := lo; j := 1;
   while starting and (i <= string_end) do begin
      if in_string[i] <> test_string[j] then starting := false;
      i := i + 1; j := j + 1;
   end;
   starts := starting;
end; (* function starts *)   

    
    (*************** this procedure works *****************)             
    
[global] procedure area(proid     : string11;
                     var area      : string10);

const
   ERROR_AREA = 'XXX       ';

begin
   if proid = ''                 then area := ERROR_AREA   else
   if starts(proid, 'P101')      then area := 'AREA_1'     else
   if starts(proid, 'P102')      then area := 'AREA_2'     else
   if starts(proid, 'P103')      then area := 'AREA_3'     else 
       ....                        ......
   area := ERROR_AREA;
end; (* procedure area *)
end.                                                        
    
    
[global] module getsym;

type
   $UWORD = [WORD] 0..65535;
   string = packed array [1..32] of char;
     
[ASYNCHRONOUS] FUNCTION lib$get_symbol (
	symbol : [CLASS_S] PACKED ARRAY [$l1..$u1:INTEGER] OF CHAR;
	VAR resultant_string : [CLASS_S,VOLATILE]
                               PACKED ARRAY [$l2..$u2:INTEGER] OF CHAR;
	VAR resultant_length : [VOLATILE] $UWORD := %IMMED 0;
	VAR table_type_indicator : [VOLATILE] INTEGER := %IMMED 0
                                         ) : UNSIGNED; EXTERNAL;
                                         
    (******************** And this function fails **********************)
    
[global] procedure getsym( sym_name  : string;
                       var sym_value : string);
begin
   lib$get_symbol(sym_name,sym_value);
end;
end.
             
    (*************** here is the GETSYM.FEX procedure that calls it ************)
                                                                
    VMS MY_DATE == "15-APR-1989 00:00:00.00"
    -SET &AREA = AREA('P101','A10');
    -SET &MY_DATE = GETSYM('MY_DATE','A23');
    -TYPE &AREA
    -TYPE &MY_DATE
    -EXIT
    
                                                                           
    (************** My output is .... **********************************)
    
    >>EX GETSYM
    > AREA_1
    
    >>

    The initial problem is in your VMS statement that assigns the symbol!
    In FOCUS each and every VMS command creates a sub-process that lasts
    only as long as the command and then goes away. So any symbol or
    logical defined (w/o /JOB) will not exist for a parent-process. 
    
    Before getting into FOCUS to run your test, define your symbol,
    globally, and then do VMS SHO SYM test-symbol right before you try your 
    sub-routine.

    Also specify in lib$get_symbol invocation that you intend to read
    a global symbol.