thread sync problem

[Gregor]

Hai :]
Beeing new to the subject I wrote the following:

...

CONNECTION_ID          n2i;
CRITICAL_SECTION      cs;     
...
//in func that creates a new thread
EnterCriticalSection(&cs);//Wait for no other thread to be initing (not using n2i)
//create the worker thread
LeaveCriticalSection(&cs);//Let the thread work
EnterCriticalSection(&cs);//When we get control again (best case we get it next) connection will be initialised and n2i will hold its id
LeaveCriticalSection(&cs);//Make sure we dont lock
return n2i;//Return id
...
//in the thread main func
EnterCriticalSection(&cs);
//init connection, set an id
//set n2i to the same id
LeaveCriticalSection(&cs);
...

___
SOLVED


Debug output from my program (MT is main thread(creator), timespamps are from my logging utility):

[MT]Trying to EnterCriticalSection
[MT]Thread created, trying to LeaveCriticalSection
[MT]Waiting for child thread
[1]Trying to EnterCriticalSection
[MT]Returning...
[000:00:00:006]: Connection:-842150451
[1]Connection created: 594102, leaving cs
[000:00:00:009]: New connection!(594102)

As you can see main thread func gets control - returns as soon as it requests. The solution was to let the child thread get control:

while(n2i!=0){//Null is not an valid id, I use it for signaling : )
		Sleep(1);
		EnterCriticalSection(&cs);//When we get control again (best case we get it next) connection will be initialised
		LeaveCriticalSection(&cs);//Make sure we dont lock
	}

[kbw]

You need to instatiate a CRITICAL_SECTION, then initialise it before use.

You can then aquire/release it in threads.

When you're done, you uninitialise it.

Do this once:

CRITICAL_SECTION cs;
InitialCriticalSection(&cs);
...
DeleteCriticalSection(&cs);

Use this whenever you need to lock a section of code.

EnterCriticalSection(&cs);
...
LeaveCriticalSection(&cs);

[Gregor]

I do have an initialize code, but I call DeleteCriticalSection on cleanup. It's my understanding this is the way it is supposed to be done.

[Incubbus]

CRITICAL_SECTION* cs;
??? why do a pointer do an critical section?...

then u need to access it by "cs" only and not "&cs"

[Gregor]

Thanks for the replies

Is that all that could be wrong? I wrote this code from scratch so i dunno if that's the case in the program...i cant acess it now, but i know it compiles fine

this prolly is not whats wrong

PS: I've run several threads putting them to sleep in the lock, other threads waited fine. As it seems the only thing not working is
EnterCS...
LeaveCS//wait for completion
EnterCS
LeaveCs
return

___
Edited to fit program code

[Incubbus]

hmm... for intereset: may u show us the complete part of waht was not working?

[Gregor]

map<int, CONNECTION>		connections;
volatile CONNECTION*		n2i;
CRITICAL_SECTION			cs;

DWORD WINAPI _worker_listener_rel( void* in ){
	lrc++;
	EnterCriticalSection(&cs);
	if(!n2i)
		return 0;
	CONNECTION*	c	= (CONNECTION*)n2i;//Make a working pointer
	LPWSTR wndname	= (LPWSTR)malloc(124);
	wsprintfW(wndname, L"RELIABLE_LISTENER#%u", lrc);
	c->wnd = CreateWindowEx(NULL,
                          L"NETRELLISTENERCLS",
                          wndname, 
                          WS_OVERLAPPEDWINDOW, 
                          300,
                          300,
                          500, 
                          400, 
                          NULL,
                          NULL, 
                          appinst, 
                          NULL);
	if(!c->wnd){
		ONERR(0, 0, (*c));
		return 0;
	}
	n2i			= 0;
	LeaveCriticalSection(&cs);
	int result;
	c->sock	= socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if(c->sock==INVALID_SOCKET){
		ONERR( (int)c->wnd, WSAGetLastError(), (*c));
		return 0;
	};
	connections.insert(pair<int, CONNECTION>((int)c->wnd, *c));//Make a copy
	WSAAsyncSelect(c->sock,c->wnd, WM_WSAASYNC, FD_READ | FD_ACCEPT | FD_CLOSE );
	//Bind and listen
	result	= bind(c->sock, (SOCKADDR*) &c->addr, sizeof(c->addr));
	if(result==SOCKET_ERROR){
		ONERR( (int)c->wnd, WSAGetLastError(), (*c));
		return 0;
	}
	result	= listen(c->sock, SOMAXCONN);
	if(result==SOCKET_ERROR){
		ONERR( (int)c->wnd, WSAGetLastError(), (*c));
		return 0;
	}
	ONINIT( (int)c->wnd, (*c) );
	MSG msg;
    while(GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
		if(msg.message==WM_KILLCONNECTION||msg.message==WM_QUIT){
			break;
		}
		DispatchMessage(&msg);
    }
	//Clean self and all subconns
	connections.erase((int)c->wnd);
	return 1;
}

int listener(unsigned short port, char flags, DATAFP onrecv, GENERALFP oninit, GENERALFP onshutdown, ERRORFP onerr){
	if(!inited){
		lasterr = 0;
		return 0;
	}
	CONNECTION* server				= new CONNECTION;
	server->onrecv					= onrecv;//If this is null than we'll only do sending
	server->oninit					= oninit;
	server->onshutdown				= onshutdown;
	server->onerror					= onerr;
	server->flags					= flags;

	server->pv.a					= (int*)malloc(sizeof(int)*participants_alloc);
	server->pv.pm					= participants_alloc;
	server->pv.pc					= 0;
	
	EnterCriticalSection(&cs);
	n2i								= server;

	server->addr.sin_family			= AF_INET;
	server->addr.sin_port			= htons( port );
	server->addr.sin_addr.s_addr	= inet_addr( "0.0.0.0" );
	server->latency					= -1;//Not connected

	server->thread					= CreateThread(	NULL, 0,
			(LPTHREAD_START_ROUTINE)(flags&LF_RELIABLE||flags&(!LF_RELIABLE|!LF_TIMECRIT))?_worker_listener_rel:_worker_listener_tc,
			(LPVOID)NULL, 0, &(server->tid));
	if(server->thread==NULL){
		n2i		= 0;
		LeaveCriticalSection(&cs);
		lasterr	= GetLastError();
		return 0;
	}
	LeaveCriticalSection(&cs);//Let the thread work;
	EnterCriticalSection(&cs);//When we get control again (best case we get it next) connection will be initialised
	LeaveCriticalSection(&cs);//Make sure we dont lock
/*Solution
while(n2i!=0){
		Sleep(1);
		EnterCriticalSection(&cs);//When we get control again (best case we get it next) connection will be initialised
		LeaveCriticalSection(&cs);//Make sure we dont lock
	}
	return (int)server->wnd;  //And return!
} */

It's a bit difrent, but no major changes. As I sed, the listener func got control right after it released it, making initialization imposible for the worker thread. It returned prematurly.

Hope it helps sum1

[kbw]

If CreateWindow fails, the critical section is never released.