xmmsc_c2c_message_t

/* In xmmsclient.h: */

typedef struct {
    int sender;
    int id;
    xmmsv_t *payload;
    ...
} xmmsc_c2c_message_t;

/*
 * The incoming c2c message is parsed in result.c into a xmmsc_c2c_message_t,
 * which is then passed to c2c notifiers.
 */

typedef int (* xmmsc_result_c2c_notifier_t) (xmmsc_c2c_message_t *c2c_msg, void *userdata);

int
callback (xmmsc_c2c_message_t *c2c_msg, void *userdata)
{
    ...

    /* No need to parse the message, just access the struct's fields */
    xmmsc_c2c_reply (c2c_msg->id, ...);
    return TRUE;
}