getprotobynumber(3) - NetBSD Manual Pages

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GETPROTOENT(3)          NetBSD Library Functions Manual         GETPROTOENT(3)


NAME

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


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <netdb.h>

     struct protoent *
     getprotoent();

     struct protoent *
     getprotobyname(const char *name);

     struct protoent *
     getprotobynumber(int proto);

     setprotoent(int stayopen);

     endprotoent();


DESCRIPTION

     The getprotoent(), getprotobyname(), and getprotobynumber() functions
     each return a pointer to an object with the following structure contain-
     ing 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 alternative 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 encountered.


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.

NetBSD 5.2                       June 4, 1993                       NetBSD 5.2