CreateThread question

thans for the reply buddy.

However, it is recommended that you check against the return value of CreateThread to check against thread creation success.

i dont understand wat you mean mate, if the sockets inside the thread connect and recv etc, that thread will have been created successfully so i dnt need to check the return value?

ah, good point mate

so do you mean something like

if (CreateThread(NULL, 0, Test_Thread, data, 0, 0) == true)

and have the thread return true/false etc?

thanks mate.

is that it thought to check if the createthread was successful? its safe coding practise i assume

hey sid. i got a problem when i check 50 emails i get a bad error saying the 'memory cant be read' on memory referencing

the callback function is like this:

int WINAPI Email_Check(HWND, HWND, char *data, char *parms, BOOL, BOOL)
{
char params[512];

sprintf(params, "%s%s", "EMAIL ", data);

if (CheckUpdateInputParams(params) == true)
{

if (CreateThread(NULL, 0, CheckEmail, params, 0, 0) != NULL) { }
}

else
EchoToMirc("Wrong parameters.");

return 1;
}

my thread is like this:

DWORD WINAPI CheckEmail(LPVOID data)
{
int nRet;

string full_data = (char*) data;

vector<string> array = Tokenize(full_data, ' ');
..
..
..
}

nope its not null terminated, should i use szData ?

it compiles fine, and the way i test this is by generating the .dll and testing it with my mirc

i cant test this any other way

DWORD WINAPI CheckEmail(LPVOID data)

the data fed into there is from the thread created in the callback function

hmm, should i null terminate the char in the callbac fucntion or the string variable in the thread

im not too sure mate :s

Note that uninitialized buffers are very dangerous.

i.e. This - char params[512];...Ought to be -
char params[512] = {0};

Pouncer, your Email_Check function returns after creating the thread, the problem is you are passing local variable to thread, and that local variable has no scope after Email_Check returns. You need to eaither wait for some event from the thread which tells you that the data is copied or you should create the params variable on heap using new.

int WINAPI Email_Check(HWND, HWND, char *data, char *parms, BOOL, BOOL)
{
// char params[512];//this is local variable
char * params = new char[512]; // fix it this way.. you need to delete it from the thread.

sprintf(params, "%s%s", "EMAIL ", data);

if (CheckUpdateInputParams(params) == true)
{

if (CreateThread(NULL, 0, CheckEmail, params, 0, 0) != NULL) { }
}

else
EchoToMirc("Wrong parameters.");

return 1;
}

& in thread code..

DWORD WINAPI CheckEmail(LPVOID data)
{
int nRet;

string full_data = (char*) data;
delete data; // to delete the string allocated in Email_check function

vector<string> array = Tokenize(full_data, ' ');
..
..
..
}

Krishnaa - good catch. :thumb:

kirishna thank you very much buddy i get no crashes now!!

also thanks sidarta for the ongoing help!!

hey sid and krishna do you guys use messenger?

Why, whats wrong with dev-archive forum ?

Nice catch on a classic threading error: Assuming that a stack variable will still be there when the thread starts executing ;)

Can't give you points Krishnaa (must "spread them around" first).

Mike

if i check up to 50 emails, will that be 50 threads? 1 thread per call?
does my code seem correct?

I used to use standard block sockets with no threads for this, but i had problems on connect() when checking up to 60 emails. thats why im going to try and make the sockets work inside a thread for each call, so am i doing it right?

In your code, yes, there would be 50 threads. Every time CreateThread is called, or _beginthreadex(), or beginthread(), or whatever thread spawner function you like, a new thread is created.

In my opinion your sockets thread logic is good, but why make the sockets non-blocking if you are doing it multi-threaded? You'll have to manage the non-blocking syncs _and_ the threading too. If you use blocking sockets (the default), you just worry about the threads. Easy.

-Greg Dolley