[alsa-devel] Why is the bufs argument for snd_pcm_writen not const?

[Takashi Iwai]

On Sun, 15 May 2016 05:05:49 +0200,
Trent Reed wrote:
> 
> Hey All,
> 
> Just wondering what the reasoning is behind snd_pcm_writen not having
> a constant variable for bufs. To me, this doesn't make sense. Does
> snd_pcm_writen make any alterations to bufs? I would expect one of the
> following declaration:
> 
> // Better, but doesn't promise that the API won't change the channel pointers.
> snd_pcm_sframes_t snd_pcm_writen(snd_pcm_t* pcm, const void** bufs,
> snd_pcm_uframes_t size);
> // Best, promises ALSA won't change channel pointers, wont change
> underlying data.
> snd_pcm_sframes_t snd_pcm_writen(snd_pcm_t* pcm, const void*const*
> bufs, snd_pcm_uframes_t size);
> 
> For now, is it safe to assume that snd_pcm_writen() doesn't alter any
> of the data in bufs passed into it? Any chance on seeing this patched
> or is there some reason for this?

We never thought of modifying the data inside the writen API
function.  The lack of const is merely the laziness.


Takashi