View source for Dynalib Miscellaneous

{{PageHeader|Dynalibs miscellaneous}}


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{{TipHeader|How to determine dynalib filename}}
At runtime it could be handy to determine the Dynalib filename of the current execution context.<br>
This can be used to display the Dynalib name in error messages within the Dynalib where the error occurred.<br>
Specially for finding the location of the issue, displaying the name of the Dynalib could really help.<br>


Use this piece of code within the Dynalib to get the filename (with or without path).<br>
It also works when executed within an executable. In that case, the exe name is determined !<br>
Both SalOutline functions are undocumented.


<pre>
! First get the current outline handle. Every dynalib in the system has an unique handle at runtime
Set nCurrentOutline = SalOutlineCurrent( )

! Now get the filename of this handle.
! The boolean parameter indicates if the receive variable sFile will have the full path (TRUE) or only the filename (FALSE)
Call SalOutlineGetFileName( nCurrentOutline, sFile, FALSE )
</pre>

The sample can be downloaded here:<br>
{{Download
|URL=http://samples.tdcommunity.net/index.php?dir=&file=WIKI_GetDynalibFilename.zip
|TEXT=WIKI_GetDynalibFilename.zip
}}


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{{TipHeader|Send message back to executable from a dynalib}}
Using the tip about sending messages to the Application Actions section which is described here:<br>

*[http://wiki.tdcommunity.net/index.php/Miscellaneous_messages#How_to_send_a_message_to_the_Application_Actions_section Send message to Application Actions section]<br>


we are able to send a message from a dynalib back to the main executable.<br>


A dynalib itself does not have a working Application Actions section, so any messages which are defined there at dynalib level are not processed.<br>


Messages like SAM_AppStartup and SAM_SqlError are ignored when the dynalib runs within an executable.<br>
The only place where messages at application level are processed is in the main executable.<br>


But there is a way to have some kind of communication between dynalibs and the main executable at runtime.<br>
A dynalib can use the described trick to send a message to the main executable message actions.<br>
When the dynalib passes a window handle which is running inside the dynalib with that message, the main executable is able to send a message back.<br>


This is the list of steps to take for this kind of message communication:<br>


* Dynalib sends an application message to the main executable message actions and passes the window handle (as number) with this message
* The main executable receives the message at application level and gets from the passed parameter the window handle of the caller
* The main executable performs whatever needed and sends a respond message back to the dynalib using the received window handle


You are able to pass custom data from the dynalib to the executable and visa versa. Constructing a string with multiple data elements and then convert it<br>
to a HSTRING (=number) and pass it as the wParam or lParam.<br>


The supplied sample shows an implementation of this.<br>


The main executable starts a FormWindow from a dynalib. The dynalib form has a button to request an action from the main executable.<br>
It sends an application message and passes the dynalib form window handle.<br>
The main executable receives this message and displays a dialog to select an action.<br>
The selected action is send back to the dynalib form and displayed there.<br>


A sample can be downloaded here:<br>
{{Download
|URL=http://samples.tdcommunity.net/index.php?dir=&file=WIKI_SendAppMsgFromDynalib.zip
|TEXT=WIKI_SendAppMsgFromDynalib.zip
}}


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{{TipHeader|How to distinguish exports}}
When your project imports several items from dynalibs, it could be helpful to see from where an item is exported.<br>
In the dynalib, place behind the <b>__Exported</b> pragma some text to indicate the source of the item :

[[Image:Exports.png]]

See sample above. Now it is easy to see where the item is from.



[[Category:Dynalibs]]