The low-level format of the addresses are different depending on the mode of communication you have chosen. A function is provided by each of the lower layers to map a user-friendly string-form address to the binary form required by the lower layers.
    void *cs_straddr(COMSTACK handle, const char *str);
   The format for TCP/IP and SSL addresses is:
    <host> [ ':' <portnum> ]
   
    The hostname can be either a domain name or an
    IP address. The port number, if omitted, defaults to 210.
   
    For TCP/IP and SSL transport modes, the special hostname "@"
    is mapped to any local address
    (the manifest constant INADDR_ANY).
    It is used to establish local listening endpoints in the server role.
   
For UNIX sockets, the format of an address is the socket filename.
When a connection has been established, you can use
    char *cs_addrstr(COMSTACK h);
   to retrieve the host name of the peer system. The function returns a pointer to a static area, which is overwritten on the next call to the function.
A fairly recent addition to the COMSTACK module is the utility function
    COMSTACK cs_create_host (const char *str, int blocking, void **vp);
   
    which is just a wrapper for cs_create and
    cs_straddr. The str
    is similar to that described for cs_straddr
    but with a prefix denoting the COMSTACK type. Prefixes supported
    are tcp:, unix: and
    ssl: for TCP/IP, UNIX and SSL respectively.
    If no prefix is given, then TCP/IP is used.
    The blocking is passed to
    function cs_create. The third parameter
    vp is a pointer to COMSTACK stack type
    specific values.
    For SSL (ssl_type) vp is an already create
    OpenSSL CTX. For TCP/IP and UNIX vp
    is unused (can be set to NULL.