getprotobynumber

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
       BSD 4.3

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



BSD                               1993-04-24                    GETPROTOENT(3)