I have defined two functions:

1) "DDE_open() return number" as:

Dim channel, number

DDEOpen "Excel", "test.xls", channel

Return channel

2) "DDE_getdata(channel number) return string" as:

Dim buffer, string

DDEGetData channel, "R1CA", buffer

Return buffer

When I run this script (with Excel running on the correct sheet):

Dim channel, number

Dim buffer, string

DDE_open channel

DDE_getdata channel, buffer

MessageBox buffer

...

the system produces this error message:
"...Request R1CA failed. DDE error: Invalid parameter passed to DDE function."

Is there something that prevents the use of DDE functions in user defined functions?
I have tested that if all DDE operations are contained in the same user defined function all works fine.

I have tested this behaviour on a Win2k machine running 24x7 Scheduler ver. 3.4.12.

Any ideas?

Thanks!

Is "R1CA" a valid Excel reference?
Isn't it supposed to be in "R[row #]C[col #]" format?

: I have defined two functions: 1) "DDE_open() return number" as: Dim
: channel, number

: DDEOpen "Excel", "test.xls", channel

: Return channel

: 2) "DDE_getdata(channel number) return string" as: Dim buffer,
: string

: DDEGetData channel, "R1CA", buffer

: Return buffer

: When I run this script (with Excel running on the correct sheet): Dim
: channel, number

: Dim buffer, string

: DDE_open channel

: DDE_getdata channel, buffer

: MessageBox buffer

: ...

: the system produces this error message: "...Request R1CA failed. DDE
: error: Invalid parameter passed to DDE function."

: Is there something that prevents the use of DDE functions in user defined
: functions?
: I have tested that if all DDE operations are contained in the same user
: defined function all works fine.

: I have tested this behaviour on a Win2k machine running 24x7 Scheduler ver.
: 3.4.12.

: Any ideas?

: Thanks!

You are right!
I made a mistake writing a simple example to explain the problem that I found on my code. It should be "R1C1".
You can try. If You write in a script:

DDEOpen "Excel", "test.xls", channel
DDEGetData channel, "R1C1", buffer

it works. But:

DDE_open channel
DDE_getdata channel, buffer

(see my previous post) doesn't work...

: Is "R1CA" a valid Excel reference?
: Isn't it supposed to be in "R[row #]C[col #]" format?

I think the problem is not in DDE but in the way you defined DDE_getdata and/or your other DDE statements

For the sake of argument if you define buffer as a number and channel as string you may get various type conversion errors and making the script unusable. Please check you statement definitions and that you pass variables correctly.

If possible post your entire script.

: You are right!
: I made a mistake writing a simple example to explain the problem that I found
: on my code. It should be "R1C1".
: You can try. If You write in a script: DDEOpen "Excel",
: "test.xls", channel
: DDEGetData channel, "R1C1", buffer

: it works. But: DDE_open channel
: DDE_getdata channel, buffer

: (see my previous post) doesn't work...

From the "Script Library" window:

DDE_getdata ( channel number ) return string

DDE_open ( ) return number

Implementations:
DDE_getdata:
-----------
Dim buffer, string

DDEGetData channel, "R1C1", buffer

Return buffer

DDE_open:
--------
Dim channel, number

DDEOpen "Excel", "test.xls", channel

Return channel

Test script:
-----------
Dim channel, number
Dim buffer, string

//DDEOpen "Excel", "test.xls", channel
DDE_open channel

//DDEGetData channel, "R1C1", buffer
DDE_getdata channel, buffer

MessageBox buffer

DDEClose channel
----------
Really simple...but doesn't work:

Line 8: Line 4: Request R1C1 failed. DDE error: Invalid parameter passed to DDE function.

The strange is that if You check the correctness of the channel number with a message box in the two user functions You see the same number...

: I think the problem is not in DDE but in the way you defined DDE_getdata
: and/or your other DDE statements

: For the sake of argument if you define buffer as a number and channel as
: string you may get various type conversion errors and making the script
: unusable. Please check you statement definitions and that you pass
: variables correctly.

: If possible post your entire script.

Got it! 24x7 keeps track of open resources (opened with DDEOpen, FileOpen, DatabaseConnect, TelnetOpen and so on). On the script terminations it automatically cleans up any resources left open. As the result when it executes your DDE_Open function it closes the DDE channel when the function terminates. And so the returned channel becomes invalid and cannot be used in other scripts.

Therefore the solution is to keep all DDE calls in one script, or open/close new channel in every script.

Hope this helps.

: From the "Script Library" window: DDE_getdata ( channel number )
: return string

: DDE_open ( ) return number

: Implementations: DDE_getdata: -----------
: Dim buffer, string

: DDEGetData channel, "R1C1", buffer

: Return buffer

: DDE_open: --------
: Dim channel, number

: DDEOpen "Excel", "test.xls", channel

: Return channel

: Test script: -----------
: Dim channel, number
: Dim buffer, string

: //DDEOpen "Excel", "test.xls", channel
: DDE_open channel

: //DDEGetData channel, "R1C1", buffer
: DDE_getdata channel, buffer

: MessageBox buffer

: DDEClose channel
: ----------
: Really simple...but doesn't work: Line 8: Line 4: Request R1C1 failed. DDE
: error: Invalid parameter passed to DDE function.

: The strange is that if You check the correctness of the channel number with a
: message box in the two user functions You see the same number...