[alsa-devel] Using MMAP feature

alberto Villa a.villa at seletech.com
Mon Jul 23 09:13:24 CEST 2012


I'm going to use the MMAP feature of ALSA. I understood I have to use 
snd_pcm_mmap_begin and snd_pcm_mmap_commit functions, but I can't 
understand the meaning of some parameters in  the snd_pcm_mmap_begin 
function: when I call this function in order to have access to the 
capture stream on a call like this:

err = snd_pcm_mmap_begin(capture, &c_area, &c_offset, &c_frames);

it keeps to return c_frames = 0: is it right ? what does  this mean? is 
the buffer full so that I can read samples or the available contiguous 
space to be read is 0?

Thank you,


Dr. Villa Alberto
Sw Engineer

SeleTech srl
via Collodi, 8 20052 Monza (MI)
tel: +39 039 5962000
fax: +39 039 9716905
email: a.villa at seletech.com
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