Question

I am writing a simple socket daemon witch listens to a port and reads the incoming data. It works fine until i choose to disconnect a client from the server…then it enters in a infinte loop recv() returns the last packet never gets to -1. My question is how can i detect that the client had been disconnected and close the thread/ socket el

My thread is as follows :

void * SocketHandler(void* lp){
    int * csock = (int*)lp;
    int test = 0;

    char buffer[1024];
    int  buffer_len = 1024;
    int  bytecount,ierr;
    memset(buffer,0,buffer_len);
    while (test == 0)
    {
    if ((bytecount = recv(*csock, buffer, buffer_len, 0))== -1){

        close(csock);
        free(csock);
        test++;
        return 0;
    }
    else
    {
        syslog(LOG_NOTICE,"%s",buffer);

    }
    }
    return 0;
};

Answer 1

A cleanly closed socket will end up in a ZERO read, while a broken connection is an error state returning -1. You need to catch the 0 return of your recv.