Error in Windows standalone

Mike Bonner bonnmike at gmail.com
Mon Apr 11 19:04:35 EDT 2011


Here is the comment from the rev dictionary that explains. Got it from the
very last comment for revopendatabase.
*
*
*revOpenDatabase, like all the revDB commands and functions is implemented
in a separate library called an External, rather than in the Revolution core
engine. *
*
*
*The database library is loaded by adding a hidden group to your stack when
deploying it. This hidden group then loads up the library by creating a
wrapper stack for the external and inserting it into the message path. It
does this on receipt of its first preOpenBackground message. *
*
*
*The consequence of this is that attempting to connect to the database
before this preOpenBackground message has initialized the external will
fail. For example, don't connect to the database on preOpenStack. Instead
use openStack or openCard.*

On Mon, Apr 11, 2011 at 5:00 PM, Mike Bonner <bonnmike at gmail.com> wrote:

> Might look at http://forums.runrev.com/viewtopic.php?f=18&t=1694 and see
> if it applies.
>
> Also noticed you mentioned a database in your post, if you're trying to
> access a database from your stack, you can't do anything relating to it in
> your preopenstack handler.  The external won't be loaded yet and will fail.
> If you look at the bottom of a dictionary entry there is a note explaining
> this, and I think it applies to all externals not just DB, so anything that
> requires a fully loaded external should go into openstack, or I think
> preopencard will work but I haven't tested it.
>
>
> On Mon, Apr 11, 2011 at 4:27 PM, Paul Foraker <paul.foraker at gmail.com>wrote:
>
>> I've built a little app that is generating a script error on Windows 7,
>> but
>> not on XP or Mac. On Win 7, the app generates this error message:
>>
>> Executing at 2:58:29 PM
>> Type
>> Object  card id 1002
>> Line    put 'Object' & tab & the short name of tObject & cr after
>> tErrorString
>> Hint    preOpenCard
>>
>> I don't have access to the Win 7 machine to run the stack in LiveCode, so
>> I'm relying on my user to run the standalone and let me know how it goes.
>> So
>> far, not so good.
>>
>> The stack is a one-card stack with a data grid and the revExternalLibrary
>> for MySQL support. All three stacks have a card id 1002, but none of them
>> have scripts. There is no "preOpenCard" handler in any object in the stack
>> files. There is no such command as in the line above in use in any script
>> that I can find.
>>
>>
>> On preOpenStack, the main stack opens a file on the user's hard drive,
>> using
>> this code:
>>
>> function actionFile pFname
>>   if the platform contains "Mac" then
>>      put specialFolderPath("Preferences") into tPath
>>   else -- windows
>>      put "0x000C" into myDocs
>>      put specialFolderPath(myDocs) into tPath
>>   end if
>>   put "/4Spires" after tPath
>>   if there is no folder tPath then create folder tPath
>>   put "/" &pFname &".txt" after tPath
>>   return tPath
>> end actionFile
>>
>> I'm passing this function the string "ActionHistoryURLs" which is the name
>> of a file containing a return-delimited list of urls the user has entered.
>> If there are none yet, I use a default url instead. I use the first one in
>> the list (or the default one) to open a file on the server containing
>> encrypted database configuration information. I decrypt the config info
>> and
>> execute a query to get the "action history" from the database, and then
>> populate the datagrid. Works fine on Mac and XP. Chokes on Win 7 in two
>> ways. First, it never gets the data from the default url; second, when the
>> user clicks that default url in a list, it should go get the data. That's
>> when the interrupt occurs, and he sends me the error message.
>>
>> I'm wondering if this error is occurring in some part of the engine code
>> instead of mine, and what's up with the single quotes in the command?
>>
>> Any ideas?
>>
>> -- Paul
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>
>



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