Hello Lazarus-List, Thursday, April 22, 2010, 2:43:04 PM, you wrote:
JS> I dont know if many of you guys who use win32 are aware of a bug / JS> limitation of sendmessage in windows , when you are trying to send a message JS> to another application , when the message gets there both lparam and wparam JS> are invalid ( or pointing to rubish ) ( i also got the same issue on You can not send data to other applications using pointers and sendmessage because they are in a different process so memory is not shared, so it is not a but nor limitation is a "by design" to allow process isolation. Windows have a special message to send data to other processes, but the amount of data is limited and it must be copied (I think it is transparent) to a shared memory. JS> the best work around i've found is to use a NamedPipe which i know is win32 JS> only ( not sure about other os's ) , i basically created a "ServerPipe" and JS> a "ClientPipe" and use this pipe to send info from the second application JS> back to my main application to get around the sendmessage issue. JS> I know alot of you guys are not using win32 but other variants of linux but JS> for the people who are using win32 this maybe of interest if you have got JS> issues with SendMessage on win32. A Pipe is designed just to to such things and they are more or less like sequential files and they share a lot of semantics. Other difference is thay pipes are not usually written to any media. JS> My Os is Win7 RTM on one pc and Win7 Retail on the other - both ultimate 64 JS> bit. & i am using pritty much the lastest SVN JS> i also suspect this method may help anyone using a DLL who needs to pass JS> objects back and forth ( i think havent tested but i think it should be JS> feasable.. ) A DLL shares the same process so you can use SendMessage or more simple a direct call to an exported procedure. A different beast is that the DLL has its own memory manager and its own RTL which is a problem to some LCL operations. -- Best regards, José -- _______________________________________________ Lazarus mailing list [email protected] http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
