Hi there, I''ve got a litte problem closing a socket which is only receiving data. After I''ve called the close() function, I have to reboot the client, because it seams to be crashed. BTW: The client which receives data runns under DOS! Has anyone, any idea? - Thank you!

My code looks like this, and it doesn''t close the socket! Why?
Hope you have any hints for me! :-)

/**** Server''s code ****/
int tcp_send( cd )
struct clientdata *cd;
{
struct tv timeout;
struct tv timeout_master;
fd_set write_fd;
fd_set write_fd_master;
int rc, i = 0;

timeout_master.tv_sec = cd->iTimeout;
timeout_master.tv_usec = 0;

FD_ZERO( &write_fd_master );
FD_SET( cd->iSocket, &write_fd_master );

while( 1 )
{
write_fd = write_fd_master;
timeout = timeout_master;

switch( select( cd->iSocket+1, 0, &write_fd, 0, (struct timeval*) &timeout ) )
{
case -1:
{
return TCP_CONNECTION_LOST;
}
case 0:
{
return TCP_TIMEOUT_WRITE;
}
default:
{
rc = send( cd->iSocket, cd->msg+i, cd->iMsgLen-i, 0 );
if( rc == -1 ) return TCP_ERROR;
i += rc;
if( i == cd->iMsgLen ) return TCP_OK;
if( i > cd->iMsgLen ) return TCP_ERROR;
}
}
}
}

/**** Client''s socketclose code ****/
int tcp_close( sock )
int* sock;
{
if( *sock )
{
shutdown( *sock, 2 );
close( *sock );
*sock = 0;
}
return 0;
}

It''s hard to say.. What DOS TCP/IP library are you using?

You say the client hangs? How does it know when to close?

A "graceful" close will usually issue a shutdown() call,
followed by recv()''ing any data left on the line, followed by a closesocket().

You''re not doing the recv()''ing after the shutdown(), but if you''re client is only reading and only closes the socket on an error or when recv() returns 0 (graceful closure), then you shouldn''t need to do the buffer-flushing recv() calls.

// CHRIS

> It''s hard to say.. What DOS TCP/IP library are you using?
PC/TCP

> You say the client hangs? How does it know when to close?
I press the escape-key and the application should close the socket.

> A "graceful" close will usually issue a shutdown() call,
> followed by recv()''ing any data left on the line, followed by
> a closesocket().
Hm, how has the server react to the shutdown call?
Or is that handled by the TCP/IP-Stack?

//Gerd

How must the server react to the shutdown call?
Or is that handled by the TCP/IP-Stack?

//Gerd

How must the server react to the shutdown call?
Or is that handled by the TCP/IP-Stack?

//Gerd

int shutdown(int socket, int how)

Disables sending, recieving, or both for a socket.

possible values for how:
0 = shutdown socket for recieving, can still send
1 = shutdown socket for sending, can still recieve
2 = shutdown socket for sending and recieving