Login
Templates, Tools and Utilities
for Clarion Developers
Templates, Tools and Utilities
|
||
|
|
|
Add a comment to an Icetips ArticlePlease add your comments to this article.
Please note that you must provide both a name and a valid email address in order
for us to publish your comment. Comments are moderated and are not visible until they have been approved. Spam is never approved!
Back to article list Search Articles Add Comment Printer friendly Direct link Clarion in general: Passing procedures as parameters 2006-02-10 -- Larry Sand Here's a trivial example of "how" you would use a procedure as a prototype.
It's difficult to come up with a non-trivial example using this technique.
It's more appropriate where you want to allow access to some data from
within a compiled module. A virtual method is very simlar and a better
choice in many circumstances. For a real world example of how a callback is
used in the Windows API, look in comp.lang.clarion for a thread with the
subject enumfonts. I posted an example on 2006.19.01 that uses a typed
procedure to prototype the callback procedure passed to the windows API.
Another similar example is the FileCallbackInterface in Clarion.
HTH,
Larry Sand
---------------------------
Program
Map
TranslatorCallbackProc Procedure(Long MsgId),Type
Translate Procedure(TranslatorCallbackProc TraslateMessageId, Long MsgId)
enTranslator Procedure(Long MsgId)
esTranslator Procedure(Long MsgId)
End
nMsg Long
Code
nMsg = 1
Translate(enTranslator, nMsg)
nMsg = 2
Translate(esTranslator, nMsg)
Translate Procedure(TranslatorCallbackProc TraslateMessageId, long MsgId)
Code
TraslateMessageId(MsgId)
Return
enTranslator Procedure(Long MsgId)
Code
Case MsgId
Of 1
message('Hello')
Of 2
message('Goodbye')
End
Return
esTranslator Procedure(Long MsgId)
Code
Case MsgId
Of 1
message('Hola')
Of 2
message('Adiós')
End
Return
Today is November 21, 2024, 6:38 am This article has been viewed 35285 times. Google search has resulted in 18 hits on this article since January 25, 2004.
|
|