Question

In got the following problem:

I made a server which is able to handle multiple connection by using select(). But select returns a client(index of FD_SET) also if the socket just got an error like “client disconnect” or whatever.

Is it possible to check a socket without calling recv(). Because to receive I need to get a buffer out of my “BufferPool“

Sample code:

int ret = recv(client, buffer_pool->get(), BUFFER_SIZE, 0);
if(ret == -1) ... // something went wrong

Well then I have to release the buffer again, and it was pretty much a waste of one buffer in my pool. (for a short time)

So isn’t it possible to check the socket without calling recv()

Answer 1

After some minutes of work and your help I just receive 1byte before receiving the full amount:

SOCKET client = ...;

char temp = 0x00;
int len = recv(client, &temp, 1, 0);
if(len == 0)
{
    // .. client error handling
    return;
}

char* buffer = m_memory_pool->Get();
len = recv(client, buffer + 1, m_memory_pool->buffer_size() - 1, 0);
buffer[0] = temp;

// data handling