#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 line from /etc/protocols that matches the protocol name name.
The getprotobynumber() function returns a protoent structure for the line that matches the protocol number number.
The setprotoent() function opens and rewinds the /etc/protocols file. If stayopen is true (1), then the file will not be closed between calls to getprotobyname() or getprotobynumber().
The endprotoent() function closes /etc/protocols.
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: