snd_pcm_multi_rewind

snd_pcm_multi_rewind

[Raymond Yau]

why the pos array can be assigned dimension by multi->slaves_count ?

does sizeof(pos) return the correct size ?

why input parameter "frames" can be modified ?

        frames = f;



static snd_pcm_sframes_t snd_pcm_multi_rewind(snd_pcm_t *pcm,
snd_pcm_uframes_t frames)
{
    snd_pcm_multi_t *multi = pcm->private_data;
    unsigned int i;
    snd_pcm_uframes_t pos[multi->slaves_count];
    memset(pos, 0, sizeof(pos));
    for (i = 0; i < multi->slaves_count; ++i) {
        snd_pcm_t *slave_i = multi->slaves[i].pcm;
        snd_pcm_sframes_t f = snd_pcm_rewind(slave_i, frames);
        if (f < 0)
            return f;
        pos[i] = f;
        frames = f;
    }
    /* Realign the pointers */
    for (i = 0; i < multi->slaves_count; ++i) {
        snd_pcm_t *slave_i = multi->slaves[i].pcm;
        snd_pcm_uframes_t f = pos[i] - frames;
        snd_pcm_sframes_t result;
        if (f > 0) {
            result = INTERNAL(snd_pcm_forward)(slave_i, f);
            if (result < 0)
                return result;
            if ((snd_pcm_uframes_t)result != f)
                return -EIO;
        }
    }
    return frames;
}

Re: snd_pcm_multi_rewind

[Clemens Ladisch]

Raymond Yau wrote:
>     snd_pcm_uframes_t pos[multi->slaves_count];

> why the pos array can be assigned dimension by multi->slaves_count ?

Because the C standard says so.

> does sizeof(pos) return the correct size ?

Yes.

> why input parameter "frames" can be modified ?
> 
>         frames = f;

Because the C standard says so.


Regards,
Clemens