unix #include <sys/socket.h>
win  #include <winsock2.h>

//int err = WSAStartup...
WSADATA wsaData;
int err = WSAStartup( MAKEWORD( 1,1), &wsaData);
SOCKET_ERROR

SOCKET s = socket( AF_INET, SOCK_STREAM/SOCK_DGRAM, 0)
INVALID_SOCKET

//struct sockaddr
struct sockaddr_in adr;
//adr.xxx=...
adr.sin_family = AF_INET;
adr.sin_port = htons( 80);
adr.sin_addr.S_un.S_addr=inet_addr( "147.32.5.8");
//lepe inet_aton linux
//gethostbyname( "www.fjfi.cvut.cz")

//err = connect( s, adr, adr_length)
err = connect( s, (struct sockaddr *)&adr, sizeof( adr))
SOCKET_ERROR

const char request[] ="GET / HTTP/1.0\n\n";
//err = send( s, buffer, length, 0);
err = send( s, request, sizeof( request)-1, 0);
SOCKET_ERROR

const char *request2 ="GET / HTTP/1.0\n\n";
err = send( s, request2, strlen( request2), 0);

//err = recv( s, buffer, length, 0);
SOCKET_ERROR
err>=0 je pocet prijatych bytu
char buff[ 1000];
err = recv( s, buff, sizeof( buff), 0);
char *buff2;
buff2 = (char *)maloc( 123456);
err = recv( s, buff2, 123456, 0);

err = close/closesocket( s);
SOCKET_ERROR

errno, GetLastError(),...

--- server

//struct sockaddr
struct sockaddr_in srv_adr;
//srv_adr.xxx=...
srv_adr.sin_family = AF_INET;
srv_adr.sin_port = htons( 12345);
srv_adr.sin_addr.S_un.S_addr=INADDR_ANY; //nebo konkretni iface

//err=bind( socket, adresa, delka_adresy)
err=bind( s, (struct sockaddr *)&srv_adr, sizeof(srv_adr));
SOCKET_ERROR

//err=listen( socket, pocet_paralelnich_prijmu_spojeni)
err=listen( s, 5);
SOCKET_ERROR

//SOCKET s1 = accept( s, adresa, delka_adresy)
struct sockaddr client_addr;
int addr_size = sizeof( client_addr);
SOCKET s1 = accept( s, &client_addr, &addr_size);
INVALID_SOCKET

send, recv, close s parametrem s1... (thread, subprocess)

err=close( s);
SOCKET_ERROR