Winsock programming - bind() issue

[iammirko]

I am a newbie to network programming. I been trying my luck with winsock and am stuck with no idea what to do.

Here is a snippet of my code:

//Bind it to a TCP/IP port
	SOCKADDR_IN SockAddr;
	SockAddr.sin_port=24;	/*Port to be used*/
	SockAddr.sin_family=AF_INET;	/*Connection Type: TCP/IP*/
	/*Listen on IP address: 127.0.0.1*/
	SockAddr.sin_addr.S_un.S_un_b.s_b1 = 127; 
	SockAddr.sin_addr.S_un.S_un_b.s_b2 = 0; 
	SockAddr.sin_addr.S_un.S_un_b.s_b3 = 0; 
	SockAddr.sin_addr.S_un.S_un_b.s_b1 = 1; 
	if(bind(socketDefinition,(SOCKADDR*)(&SockAddr),sizeof(SockAddr))==SOCKET_ERROR) 
		printf("Attempt to bind failed.");

The code is compiling properly but output is: "Attempt to bind failed."

Any suggestions?

Thanks.

[iammirko]

My full code looks like this:

#include<stdio.h>
#include<conio.h>
#pragma comment(lib,"mpr.lib")
#pragma comment(lib,"wsock32.lib")
// -lws2_32 compile flag
#include<stdlib.h>
#include<winsock2.h>

int main()
{
	//Initialise Winsock API with version details specified in MAKEWORD
	WSADATA WsaDat;
    if(WSAStartup(MAKEWORD(1,1),&WsaDat)!=0)
		printf("\nWSA Initialization failed.");
	
	//Define a socket using the socket() function
	SOCKET socketDefinition;
	socketDefinition=socket(AF_INET,SOCK_STREAM,0);
	if(socketDefinition==INVALID_SOCKET)
		printf("\nSocket creation failed!");
		
	//Bind it to a TCP/IP port
	SOCKADDR_IN SockAddr;
	SockAddr.sin_port=24;	/*Port to be used*/
	SockAddr.sin_family=AF_INET;	/*Connection Type: TCP/IP*/
	/*Listen on IP address: 127.0.0.1*/
	SockAddr.sin_addr.S_un.S_un_b.s_b1 = 127; 
	SockAddr.sin_addr.S_un.S_un_b.s_b2 = 0; 
	SockAddr.sin_addr.S_un.S_un_b.s_b3 = 0; 
	SockAddr.sin_addr.S_un.S_un_b.s_b1 = 1; 
	if(bind(socketDefinition,(SOCKADDR*)(&SockAddr),sizeof(SockAddr))==SOCKET_ERROR) 
		printf("Attempt to bind failed.");
	
	//Listen to a socket
	listen(socketDefinition,1); 
	
	//Wait/Loop until a connection received 
	SOCKET TempSock = SOCKET_ERROR; 

	while(TempSock==SOCKET_ERROR) 
		TempSock=accept(socketDefinition, NULL, NULL);
	socketDefinition=TempSock;
	
	//Get information on who connected
	SOCKADDR Addr; 
	accept(socketDefinition,&Addr,(int*)sizeof(Addr));
	
	//Connect to the incoming request with port and address of the one trying to connect to
	if (connect(socketDefinition,(SOCKADDR *)(&SockAddr),sizeof(SockAddr))!=0)
		printf("Failed to establish connection with server.");
		
	//The sending function
	char* str="Hello";
	int RetVal=SOCKET_ERROR; 
	while (RetVal==SOCKET_ERROR)
	{
		RetVal = recv(socketDefinition,str,strlen(str)+ 1,0);
		if ((RetVal==0)||(RetVal==WSAECONNRESET))
		{
			printf("Connection closed at the sending moment.");
            break;
        }
	}
	
	//Receive in the same looping manner as above
	while (RetVal==SOCKET_ERROR)
	{
       RetVal=recv(socketDefinition,str,50,0);
       if ((RetVal == 0)||(RetVal == WSAECONNRESET))
		{
			printf("Connection closed at other end."); 
            break;
		}
	}
	
	getch();
	return 0;
}

[nezachem]

Call GetLastError() and display it with FormatMessage(). That will give you textual explanation of why "Attempt to bind failed".

Besides that, the port value in sockaddr should be in the network byte order. Use htons() (or a whatever winsock provides for that matter). sin_addr is also conventionally assigned via interface function (like inet_addr() or inet_aton()).

Finally, it is highly recommended to zero out the entire sockaddr before filling it up.

[iammirko]

How to use GetLastError. I am a newbie and the code was from an online tutorial with minor modifications.