getservbyport(2)                                       getservbyport(2)

  getservbyport()

  NAME

    getservbyport(), getservbyname(), getservent(), setservent(), endservent()
    - get service entry

  SYNOPSIS

    #include 

    struct servent *getservent(void)
    struct servent *getservbyname (char *name, const char *proto)
    struct servent *getservbyport (int port, const char *proto)
    void setservent (int stayopen)
    void endservent (void)

  DESCRIPTION

    The getservent(2), getservbyname(2) and getservbyport(2) functions each
    return a pointer to an object with the following structure containing the
    information from a network services database.

    struct servent {
        char * s_name;      /* official name of service */
        char ** s_aliases;  /* alias list */
        int s_port;         /* port service resides at */
        char * s_proto;     /* protocol to use
    };

    The members of this structure are:

    s_name
        The official name of the service.

    s_aliases
        A zero terminated list of alternate names for the service.

    s_port
        The port number at which the service resides. Port numbers are
        returned in network byte order.

    s_proto
        The name of the protocol to use when contacting the service.

    The getservent(2) function reads the next line of the file, opening the
    file if necessary.

    The setservent(2) and endservent(2) functions are no-ops, provided for
    portability.

    The getservbyname(2) and getservbyport(2) functions return information
    from a matching protocol name or port number. If a protocol name is also
    supplied (proto is non-NULL), searches must also match the protocol.

  NOTES

    These functions use static data storage; if the data is needed for future
    use, it should be copied before any subsequent calls overwrite it.

  RETURN VALUES

    Returns NULL pointer on end of file (EOF) or error.

  FILES

    These functions make use of the following files:

    %WINDIR%/system32/drivers/etc/services
        The network services database, where %WINDIR% is the Windows
        installation directory.

  SEE ALSO

    getprotoent(2)

  USAGE NOTES

    None of these functions are thread safe.

    None of these functions are async-signal safe.