GETPROTOENT(3) Linux Programmer s Manual GETPROTOENT(3)

NAME getprotoent, getprotobyname, getprotobynumber, setprotoent, endprotoent - get protocol entry

SYNOPSIS #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);

DESCRIPTION The getprotoent() function reads the next line from the file /etc/pro- tocols and returns a structure protoent containing the broken out fields from the line. The /etc/protocols file is opened if necessary.

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:

p_name The official name of the protocol.

p_aliases A zero terminated list of alternative names for the protocol.

p_proto The protocol number.

RETURN VALUE The getprotoent(), getprotobyname() and getprotobynumber() functions return the protoent structure, or a NULL pointer if an error occurs or the end of the file is reached.

FILES /etc/protocols protocol database file

CONFORMING TO 4.3BSD, POSIX.1-2001.

SEE ALSO getnetent(3), getservent(3), protocols(5)

BSD 1993-04-24 GETPROTOENT(3)