Function returning pointers

[michaelklein]

I've created a function f_statusmsg() which returns 2 pointers, f_statusmsg.status and f_statusmsg.message. When I test the function using the following statement in the Interactive window, it works fine:

? f_statusmsg("P2100101").message
="OK"

However, when I put f_statusmsg(barcodeid).message into the default value in field rules, I get an error message - see attached image. Note: The Expression Builder evaluates the function just fine, but when I try to save the field rules I get the error. Can anyone provide a solution or workaround here?

--Michael

[JohnZaleski]

RE: Function returning pointers

My workaround would be to have the function accept a second argument that determines whether a status or a message is returned. Something like:
status_msg(barcode,1) for a status
status_msg(barcode,2) for a message

[michaelklein]

RE: Function returning pointers

I've already created a 2nd function which does exactly what you suggest. The problem is that I'd prefer to only run the function 1 time as it opens and closes a few tables each time it runs, so speed can become a factor.

--Michael

[whanigsberg]

RE: Function returning pointers

Have you by any chance tried using eval()?

Bill

[Stan Mathews]

RE: Function returning pointers

From the attached image it appears you are trying to have a default value, by field rule, for the barcodeid field in the bctempid table to be

f_statusmsg(bctempid-"barcodeid).message

Isn't that rather circular logic?

Try using your field rule for the default expression for another (new) field.

[michaelklein]

RE: Function returning pointers

Stan,

Thanks -- a 2nd set of eyes always helps "s". Although you are correct, it still doesn't work even if I use the function for a default value on a different, *non-circular* field. I have taken Bill's suggestion to try *eval()* and that apppears to do the trick.

--Michael

[michaelklein]

RE: Function returning pointers

Bill,

Thanks. That worked perfectly!

--Michael

[Blake]

RE: Function returning pointers

I notice this is in field rules...

How do you use the second pointer?

[michaelklein]

RE: Function returning pointers

I assign f_statusmsg().message to a message field in the bctempid table. This field is then displayed as a column in a browse. Basically what I'm doing is using a browse to simulate the entry of membership numbers and corresponding display of status information about the specific member number just entered. It actually works very nicely.

--Michael

[Blake]

RE: Function returning pointers

Michael,

If you have a chance to boil that down to just the function, I'd be interested in seeing it. It sounds rather clever. :-)

===Blake===

[michaelklein]

RE: Function returning pointers

Blake,

I'm not sure how clever it is, but here's the function:

FUNCTION fp_statusmsg AS P (cMember as C)

DIM cMessage as C
DIM cStatus as C
DIM lMemberActive as L
DIM lMemberFound as L
DIM pMemactive as P
DIM pMemdat as P

pMemactive = table.open("bcactive")
pMemactive.index_primary_put("bcaidx1")
pMemdat = table.open("bcmemdat")
pMemdat.index_primary_put("bcmidx1")

cMessage = ""
cStatus = ""

if .NOT. isnull(cMember)
lMemberFound = pMemdat.fetch_find(cMember) " 0
lMemberActive = pMemactive.fetch_find(pMemdat.Clubcode + pMemdat.Pc51memno) " 0
if .NOT. lMemberFound
cMessage = "Member is not in membership database!"
cStatus = "6"
elseif lMemberActive
cMessage = "Card already used today!"
cStatus = "1"
else
cMessage = "OK"
cStatus = "0"
end if
end if

fp_statusmsg.message = cMessage
fp_statusmsg.status = cStatus

pMemdat.close()
pMemactive.close()

END FUNCTION

In the field rules of the temporary table I'm browsing, I assign the default value of the StatusMsg field (at start of data entry) to eval("fp_statusmsg().message").

--Michael

[JohnZaleski]

RE: Function returning pointers

"The problem is that I'd prefer to only run the function 1 time as it opens and closes a few tables each time it runs, so speed can become a factor."

Michael,
I'm probably missing something here, but I don't see how using a pointer variable would speed things up.
Every time you reference either fp_statusmsg().message or fp_statusmsg().status, the function runs, opening up tables ect,so where is the speed up???
John

[michaelklein]

RE: Function returning pointers

John,

I meant run it one time per new record entered.

--Michael

[JohnZaleski]

RE: Function returning pointers

Michael,
I'm still missing something.
Any reference to something like eval(fp_statusmsg(barcodeid).message or .status) causes the function to run just as if you referenced f_statusmsg(barcodeid).
The only way I see a help would be if you had a global pointer variable equal to the function:
pvhold = f_statusmsg(barcodeid).
Then pvhold.status and pvhold.message would be availabe with the function running just once.
John