#include <netdb.h> struct protoent *getprotoent(void); struct protoent *getprotobyname(const char *name); struct protoent *getprotobynumber(int proto); void setprotoent(int stayopen); void endprotoent(void);
The getprotobyname() function returns a protoent structure for the entry from the database that matches the protocol name name. A connection is opened to the database if necessary.
The getprotobynumber() function returns a protoent structure for the entry from the database that matches the protocol number number. A connection is opened to the database if necessary.
The setprotoent() function opens a connection to the database, and sets the next entry to the first entry. If stayopen is non-zero, then the connection to the database will not be closed between calls to one of the getproto*() functions.
The endprotoent() function closes the connection to the database.
The protoent structure is defined in <netdb.h> as follows:
struct protoent {
    char  *p_name;       /* official protocol name */
    char **p_aliases;    /* alias list */
    int    p_proto;      /* protocol number */
}
The members of the protoent structure are: