Zephyr

BUG OF THE MONTH | Unreachable code

V547 Expression ‘disp’ is always true. lv_disp.c 148

uint32_t lv_disp_get_inactive_time(const lv_disp_t * disp)
{
    if(!disp) disp = lv_disp_get_default();
    if(!disp) {
        LV_LOG_WARN("lv_disp_get_inactive_time: no display registered");
        return 0;
    }

    if(disp) return lv_tick_elaps(disp->last_activity_time);

    lv_disp_t * d;
    uint32_t t = UINT32_MAX;
    d          = lv_disp_get_next(NULL);
    while(d) {
        t = LV_MATH_MIN(t, lv_tick_elaps(d->last_activity_time));
        d = lv_disp_get_next(d);
    }

    return t;
}

The function returns if disp is a null pointer. This is followed by an opposite check – whether the disp pointer is non-null (which is always true) – and the function returns all the same.

Because of this logic, part of the code in the function’s body will never get control.

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