The exact equiv of what you showed would be this:

static int pbx_dial(switch_core_session_t *session, void *data)
{
    const switch_application_interface_t *application_interface;
    int ret;
    char *app_name = "bridge";
    char *app_arg = (char *) data;

    if ((application_interface = switch_loadable_module_get_application_interface(app_name))) {
        application_interface->application_function(session, app_arg);
        return 0;
    } else {
        return -1;
    }
}