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Obviously a bug....with TRAD, it just never seems to end, does it ?
> -----Original Message-----
> From: Mike Gossland [mailto:mga@xxxxxxxx]
> Sent: Thursday, May 08, 2003 3:21 PM
> To: brendan@xxxxxxxxxxxxxx; Omega-List
> Subject: Re: External DLLs in TS7 vs. 2000i
>
>
>
> 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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