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Nice work, Brendan! I learned quite a bit from your presentation. I can only suggest you try to take this up in the TS forum.
I too have seen some stranded orchart.exe apps lying around after I close things down, but I suspected my code was somehow responsible for this.
The main difference I've noticed between TS7 and 2000i is that in TS7 when you turn the status of the indicator off, the DLL is not unloaded. You have to close the page to get it out of memory. A bit of an inconvenience.
On a separate but related topic, it would be nice to see TS implement a "Refresh Indicator" from the popup menu, doing the same thing as toggling the status off and on. Maybe I should suggest it for a poll, but who else would vote for it?
regards,
Mike Gossland
>Hello,
>
>(This e-m is being individually sent to several Omega / TradeStation
>lists which have previously had TradeStation DLL threads.}
>
>This e-m is to outline some behavior I'm seeing using a DLL w/TS
>2000i vs. v7. If anyone else has seen this behavior, or can shed
>light on it, I'd love to hear it. Otherwise perhaps this can help
>someone who's currently (or planning) to use a DLL w/v7.
>
>1. When using a 'legacy' DLL (that written to export to the
>Dll_{Add,Context,Free()} APIs introduced in 2000i) w/TS7 I've noticed
>that it does not appear to unload the DLL when an indicator using the
>DLL is removed from a chart.
>
>I log to a file when my DLL starts and stops. Using 2000i (and I
>believe v6) I see a log entry for both the DLL startup and shutdown.
>
>Using TS7 I see only the log entry for the startup. In addition
>after shutting down TS7 I notice that orchart.exe remains running (as
>seen using TaskMan). When I kill orchart.exe my DLL is unloaded.
>
>It appears that this is one manifestation of a bug (gasp!) in TS7.
>The other manifestation is as follows:
>
>Suppose I open a workspace and add an indicator (which uses my DLL).
>I then close the workspace (either deleting the indicator or not, it
>doesn't change the behavior). I still have a orchart.exe running. I
>re-open the workspace, now I have two orchart.exes running. I add my
>indicator and close the workspace, still have two orchart.exes
>running. I re-open the workspace, now I have three orchart.exes
>running.
>
>>From the behavior it seems that someone forgot to do a FreeLibrary()
>someplace...
>
>2. I've also noticed that the use of Dll_Add() / Dll_Context()
>appears to have changed. In 2000i Dll_Context() would be called
>prior to calling into my DLL for *each* data point.
>
>In TS7 it doesn't appear that Dll_Context() is ever called. This
>means that if you have more than one indicator, etc. using the DLL,
>the DLL won't be able to distinguish between them.
>
>Looking at the TS7 EasyLanguage Extension SDK I see that TradeStation
>Technologies appears to have deprecated the Dll_{Add,Context,Free}()
>constructs and replaced them with a model built on 'events'.
>
>At first review this might be a good thing. With the ability to get
>an IEasyLanguageObject when a DLL function is called one can get the
>Open, High, Low, Close, etc. w/o requiring the user to pass this in
>as part of the function call.
>
>It seems to me though that to support *legacy* DLLs that TT should
>have continued to support the Dll_Context(), yes?
>
>I've modified my DLL and EL code to support v7s changes and I'm able
>to get around the Dll_Context() problem - I can differentiate between
>two or more uses of my DLL. My soln to the stranded orchart.exe is
>to kill the process by hand.
>
>3. When using the IEasyLanguageObject * form of a DLL export, it
>doesn't appear that you can use a passed in float * to return a value
>e.g.
>
>In 2000i if you had a function which returned a value like so:
>
>int __stdcall
> MyFunc(float *p_fResult)
>{
> *p_fResult = <something>;
>}
>
>this won't work:
>int __stdcall
> MyFunc(IEasyLanguageObject *p_pEL, float *p_fResult);
>{
> *p_fResult = <something>;
>}
>
>Instead I needed to do this:
>int __stdcall
> MyFunc(IEasyLanguageObject *p_pEL, const char *p_pszVarName);
>{
> if (p_pEL)
> {
> p_pEL->Variables[p_pszVarName]->Value[0] = <something>;
> }
> else
> {
> // Error
> } /* end if-else */
>}
>
>
>Cheers,
>Brendan
>---
>Brendan B. Boerner
>brendan@xxxxxxxxxxxxxx
>Karakhorum Ventures, Inc.
>www.Karakhorum.com
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