public static extern int pm_blink(out pm_context pm);
public static extern int pm_set_frequency(out pm_context pm, UInt64 freq);
public static extern int pm_type(out pm_context pm, out UInt32 type);
public static extern int pm_reset(out pm_context pm);
public static extern int pm_set_averages(out pm_context pm, UInt16 avg);
public static extern int pm_open(out pm_context pm, UInt32 serial);
public static extern int pm_measure(out pm_context pm, out float power);
public static extern int pm_init(out pm_context pm);
public static unsafe extern sbyte* pm_get_error_string(out pm_context pm);
public static extern int pm_close(out pm_context pm);