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GETPROTOENT(3) BSD Library Functions Manual GETPROTOENT(3)
NAME
getprotoent, getprotobynumber, getprotobyname, setprotoent, endprotoent -- get protocol en-
try
LIBRARY
Standard C Library (libc, -lc)
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(), getprotobyname(), and getprotobynumber() functions each return a pointer
to an object with the following structure containing the broken-out fields of a line in the
network protocol data base, /etc/protocols.
struct protoent {
char *p_name; /* official name of protocol */
char **p_aliases; /* alias list */
int p_proto; /* protocol number */
};
The members of this structure are:
p_name The official name of the protocol.
p_aliases A zero terminated list of alternate names for the protocol.
p_proto The protocol number.
The getprotoent() function reads the next line of the file, opening the file if necessary.
The setprotoent() function opens and rewinds the file. If the stayopen flag is non-zero,
the net data base will not be closed after each call to getprotobyname() or
getprotobynumber().
The endprotoent() function closes the file.
The getprotobyname() function and getprotobynumber() sequentially search from the beginning
of the file until a matching protocol name or protocol number is found, or until EOF is en-
countered.
RETURN VALUES
Null pointer (0) returned on EOF or error.
FILES
/etc/protocols
SEE ALSO
protocols(5)
HISTORY
The getprotoent(), getprotobynumber(), getprotobyname(), setprotoent(), and endprotoent()
functions appeared in 4.2BSD.
BUGS
These functions use a static data space; if the data is needed for future use, it should be
copied before any subsequent calls overwrite it. Only the Internet protocols are currently
understood.
BSD June 4, 1993 BSD
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