Message cross threads

stevenson

hi, in one procedure I post message to thread with wParam, the thread accepted my message, but wParam is corrupted. Here is the code: In the procedure

MsgParam \*pSendParam=new MsgParam;
pSendParam->pBuf=pBuf;
pSendParam->nLen=nLen;

PostThreadMessage(tid,WM\_HYDRO\_RXD\_ARRIVAL,(WPARAM)pSendParam,0);

In thread Function

case WM_HYDRO_RXD_ARRIVAL:
pRecParam=(MsgParam*)msg.wParam;

before PostThreadMessage, pSendParam is correct(in this case, it's f5f5090574a05200), but in case WM_HYDRO_RXD_ARRIVAL, the value is corrupted as 44bf4a5f01000000, How to transfer data correctly? Extreme programming. Do the No.1

stevenson

appreciation for any information on this post. Thanks Extreme programming. Do the No.1

Daniel Lohmann

You are developing on Win64? Wow :cool: Your problem sounds a bit strange. It should work as you described, I can't find anything conspicuous in your code. I would suppose a subtle side effect: - Are you sure the value of WM_HYDRO_RXD_ARRIVAL is unique and you are not accidently catching the wrong message? - Are you sure _W64 is always defined and really all data types are used as 64 bit types? - Did you monitor any other side effects that look like memory corruption occuring somewhere in your app? - Does the same problem appear in a small test app? (Hm the above looks a bit like the generic "are you sure the power cable is plugged in" hotline answer :-O ) Good luck! -- Daniel Lohmann http://www.losoft.de (Hey, this page is worth looking! You can find some free and handy NT tools there :-D )

includeh10

the code is absolutely incorrect. try to send an int int i=5; PostThreadMessage(tid,WM_HYDRO_RXD_ARRIVAL,(WPARAM)i,0); it will be OK. when u pass an object created by new, normally it can not be passed to another thread in the simple way. i don't know how to do it, but i did similar thing in COM, if u know COM, try same idea that how COM passes object to another COM (they are in 2 threads). good luck. includeh10

Daniel Lohmann

What? :wtf::omg: Sorry, includeh10, but you seem to completly misunderstood the concept of threads. You can pass pointers between threads as long as you make sure they reside in the same process. All threads inside a process share the same address space, therefore any address reference is valid and accessable by every thread. Actually this easiness of inter-thread communication is the main reason we use threads instead of processes. COM puts a lot of "magic stuff" (like apartments, free threaded marshaller, ...) around this, because it has to guarantee that it even works if both thread reside in different processes or even on different machines. -- Daniel Lohmann http://www.losoft.de (Hey, this page is worth looking! You can find some free and handy NT tools there :-D )

Daniel Lohmann

BTW: Your E-Mail address seems to be incorrect. I got an "Undeliverable Mail" message for steven_wng@sina.com on my previous post. Hope you check the forum as well :-) -- Daniel Lohmann http://www.losoft.de (Hey, this page is worth looking! You can find some free and handy NT tools there :-D )

includeh10

i am pretty sure that an object can be past from one COM to another even 2 COM are in the same process (or create by same process). as i said, i never use threads in this way, but i don't think the code would work. anyway, do further test to get right answer. good luck includeh10

Kelly Herald

Have you tried passing pSendParam through the LPARAM parameter? PostThreadMessage(tid,WM_HYDRO_RXD_ARRIVAL,0,(LPARAM)pSendParam); and changing your thread to this: pRecParam=(MsgParam*)msg.lParam; Kelly Herald Software Developer Micronpc, LLC

stevenson

hi, yeath, I really can pass int i through the gap,but can't pass a struct. I don't know why too. As far as COM is concerned, Inside COM and Essential COM is all what I have. I determined to check it out. Thanks Extreme programming. Do the No.1