Selecting a protocol (Internet domain)

To obtain a particular protocol, select the protocol number


as defined within the communication domain. For the Internet domain, the available protocols are defined in netinet/in.h.
You can also use one of the library routines such as getprotobyname in getprotoent(SLIB):

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
/* ... */
pp = getprotobyname("tcp");
s = socket(AF_INET, SOCK_STREAM, pp->p_proto);