[alsa-devel] Why is the bufs argument for snd_pcm_writen not const?
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?
Thanks, - Trent Reed
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
Thanks Takashi,
I wasn't able to find anything about this in the documentation. Perhaps if it isn't changed in the API, it could be added as a @note for Doxygen in the functions?
- Trent Reed On May 15, 2016 11:58 PM, "Takashi Iwai" tiwai@suse.de wrote:
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
On Mon, 16 May 2016 09:06:06 +0200, Trent Reed wrote:
Thanks Takashi,
I wasn't able to find anything about this in the documentation. Perhaps if it isn't changed in the API, it could be added as a @note for Doxygen in the functions?
A patch is always welcome :)
Takashi
- Trent Reed
On May 15, 2016 11:58 PM, "Takashi Iwai" tiwai@suse.de wrote:
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
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participants (2)
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Takashi Iwai -
Trent Reed