#include <sys/types.h> #include <netinet/in.h>
ulong htonl(u_long hostlong);
u_short htons(u_short hostshort);
u_long ntohl(u_long netlong);
u_short ntohs(u_short netshort);
Safe
These routines convert 16 and 32 bit quantities between network byte order and host byte order. On some architectures these routines are defined as NULL macros in the include file <netinet/in.h>. On other architectures, if their host byte order is different from network byte order, these routines are functional.
These routines are most often used in conjunction with Internet addresses and ports as returned by gethostent() and getservent(). (See gethostbyname(3N) and getservbyname(3N) respectively.)