I cant see how it can be safe. I was stumped as well when I wanted to send a string in a message. I had to abandon my ideas.... :-( Let me know if you have any joy.
From: "Paul Lowman" <[EMAIL PROTECTED]> To: "Delphi List" <[email protected]> Date sent: Thu, 24 Nov 2005 16:22:04 +1300 Copies to: Subject: [DUG] Reference counting Send reply to: NZ Borland Developers Group - Delphi List <[email protected]> <mailto:[EMAIL PROTECTED]> <mailto:[EMAIL PROTECTED]> [ Double-click this line for list subscription options ] Heres one for the gurus - Assume a long string variable is declared locally to a method and is assigned a string and the string variable is then typecast as an integer and used in - say - a windows message by assigning it to the message lparam. The question is when the message is received by another form / thread is it valid to then typecast the lparam back to a string and use it ? I have tried many variations of this scenario and it seems to work OK but am uneasy about whether or not this is safe. I assume it isn't as the local string variable (which points to the actual string) is on the stack and is not maintained after the method is exited but what I really am concerned about is the reference count for the string - has it been increased by typecasting it to an integer / pointer whatever ... I have used some of Marco Cantu's code to try and examine the strings reference count and it always appears to be -1 if the string is a local variable although it works correctly for field or global. All very confusing :-) I would like to know how the code knows when to inc / dec / dispose the stirng / array reference count. Cheers Paul Lowman _______________________________________________ Delphi mailing list [email protected] http://ns3.123.co.nz/mailman/listinfo/delphi Regards Rohit ====================================================================== CFL - Computer Fanatics Ltd. 21 Barry's Point Road, AKL, New Zealand PH (649) 489-2280 FX (649) 489-2290 email [EMAIL PROTECTED] or [EMAIL PROTECTED] ====================================================================== _______________________________________________ Delphi mailing list [email protected] http://ns3.123.co.nz/mailman/listinfo/delphi
