DragonFly On-Line Manual Pages

GETPROTOENT(3)        DragonFly Library Functions Manual        GETPROTOENT(3)

NAME
     getprotoent, getprotoent_r, getprotobynumber, getprotobynumber_r,
     getprotobyname, getprotobyname_r, setprotoent, endprotoent - get protocol
     entry

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <netdb.h>

     struct protoent *
     getprotoent(void);

     int
     getprotoent_r(struct protoent *, char *, size_t, struct protoent **);

     struct protoent *
     getprotobyname(const char *name);

     int
     getprotobyname_r(const char *, struct protoent *, char *, size_t,
         struct protoent **);

     struct protoent *
     getprotobynumber(int proto);

     int
     getprotobynumber_r(int, struct protoent *, char *, size_t,
         struct protoent **);

     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 encountered.

     The getprotoent_r(), getprotobynumber_r(), and getprotobyname_r()
     functions are reentrant versions of the above functions that take a
     pointer to a protoent structure which is used to store state information.
     The structure must be zero-filled before it is used and should be
     considered opaque for the sake of portability.  These functions also take
     a pointer to another protoent structure which is used to store the
     results of the database lookup.

RETURN VALUES
     The getprotoent(), getprotobynumber(), and getprotobyname() functions
     return a pointer to a protoent structure on success or a null pointer if
     end-of-file is reached or an error occurs.

     The getprotoent_r(), getprotobynumber_r(), and getprotobyname_r()
     functions return 0 on success or -1 if end-of-file is reached or an error
     occurs.

FILES
     /etc/protocols

SEE ALSO
     protocols(5)

STANDARDS
     The getprotoent(), getprotobynumber(), getprotobyname(), setprotoent(),
     and endprotoent() functions conform to IEEE Std 1003.1-2004 ("POSIX.1").

     The getprotoent_r(), getprotobynumber_r(), and getprotobyname_r()
     functions are not currently standardized.

HISTORY
     The getprotoent(), getprotobynumber(), getprotobyname(), setprotoent(),
     and endprotoent() functions appeared in 4.2BSD.

     The getprotoent_r(), getprotobynumber_r(), and getprotobyname_r()
     functions appeared in DragonFly 2.1.

BUGS
     These functions use a thread-specific 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.

DragonFly 5.5-DEVELOPMENT         May 4, 2019        DragonFly 5.5-DEVELOPMENT