C++ socket and thread [modified]

[canard29]

Hi, I have a small programm which listen a socket in a new thread. but I want to restart the porgramm after the first message. Start the thread in main.cpp

hThread = CreateThread( 
				NULL,                       
				0,                           
				ThreadFunc,                
				&dwThrdParam,              
				0,                          
				&dwThreadId);  

The programm :

DWORD WINAPI ThreadFunc( LPVOID lpParam ) 
{ 
			WSAStartup(MAKEWORD(2,2),&initialisation_win32);
			socket_recevoir=socket(AF_INET,SOCK_DGRAM,0);
			information_recevoir.sin_family=AF_INET;
			information_recevoir.sin_addr.s_addr=INADDR_ANY; 
			information_recevoir.sin_port=htons(25);

			bind(socket_recevoir,(struct sockaddr*)&information_recevoir,sizeof(information_recevoir));

			tempo=sizeof(information_recevoir); 
			nb_caracters=recvfrom(socket_recevoir,buffer,1515,0,(struct sockaddr*)&information_recevoir,&tempo);
			buffer[nb_caracters]=0;

			if (nb_caracters >0)
			{
				ExecuteCommand(buffer, NULL, 0);
			}
	
		
			closesocket(socket_recevoir);
		

	return 0; 
} 

In main.cpp, I want to call again this programm. Can you help me please ?

modified on Monday, April 5, 2010 10:42 AM

[Moak]

Hi, from what I can see the socket is not doing anything or you did not post the full code. The server socket never calls listen or accept. Maybe you could provide us more information? In a nutshell there a three possible designs for a server: your server handles one client at a time (example), uses asynchronous I/O (multiple connections in a single thread context) or uses multi threading (one connection per thread). Here are some links that might come helpful: - Internet / Network - CodeProject[^] - Beej's guide to networking programming[^] - Winsock Programmer's FAQ[^] Last two have working client/server examples in section 6. Hope it helps :) /M

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modified on Monday, April 5, 2010 5:40 AM

[canard29]

this application execute this line : ExecuteCommand(buffer, NULL, 0) but only one time. I will check your links

[Moak]

Could you please format your code with <pre> tag for readability and remove the French comments? It was quite hard to read. Looking again at your code, you have a blocking UDP socket waiting for a connection, which calls ExecuteCommand() and exists the thread? Perhaps all you are looking for is a for loop (and a way to programatically exit the worker thread)? :) /M

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modified on Monday, April 5, 2010 9:10 AM

[canard29]

Think you for your help. I removed the comments and used

. I hope it's easier to read.
yes, you're right, I want to add a loop but I don't where in my code.

Think you

[Moak]

Okay thanks for the formatting! :) Let my try to help.... put the loop around the blocking part (pseudocode):

socket();
bind();
for(;;)
{
recvfrom();
if(ok) ExecuteCommand();
}
closesocket();

Right now the worker thread has no exit condition, you probably want to add one in order to avoid terminating the thread the hard way at application exit. Also have a look at some other issues, e.g. starting from this line

nb_caracters=recvfrom(socket_recevoir,buffer,1515,0,(struct sockaddr*)&information_recevoir,&tempo);

should become something like

int nb_caracters = recvfrom(socket_recevoir, buffer, sizeof(buffer)-1, 0, (struct sockaddr*)&information_recevoir, &tempo);
if(nb_caracters > 0) //data was received and no socket error (return value -1)?
{
buffer[nb_caracters] = 0; //one byte was reserved for terminating Null
ExecuteCommand(buffer, NULL, 0); //lets hope it was a complete package and also not a duplicate
}

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modified on Monday, April 5, 2010 3:34 PM