Re: return value of snd_pcm_hw_params_set_rate_near

[Doug McLain <nostar@comcast.net>]

http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___h_w___params.html#a58

Thanks for the reply...

P.S.  I was mistaken, the doc does in fact define arg 3 as 'pointer to 
int' and describes the action.  The return value is the only problem.

Jaroslav Kysela wrote:

>On Mon, 1 Mar 2004, Doug McLain wrote:
>
>  
>
>>According to the alsa documentation, the return value of 
>>snd_hw_params_set_rate_near is the 'approximate chosen rate', and the 
>>3rd arg being type 'int'.  The two tutorials at the documentation 
>>section of the alsa-project website both hold true to this with code like:
>>
>>exact_rate = snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, rate, &dir);
>>    if (dir != 0) {
>>      fprintf(stderr, "The rate %d Hz is not supported by your hardware.\n 
>>                       ==> Using %d Hz instead.\n", rate, exact_rate);
>>    }
>>
>>
>>
>>After unsuccesful attempts at using this function this way (I'm learning 
>>linux audio software devel starting with alsa drivers and user 
>>interface), I went into the aplay source and found the version that 
>>tests a before and after version of arg 3 (which is a pointer to int 
>>that gets changed to the result rate by the function) and tests the 
>>return only for err. I assume this function changed?  Im at the learning 
>>stage so I'm probably stating the obvious, but when your new sometimes 
>>reassurance from someone that knows helps.  Is the documentaion just 
>>behind, or did this slip by unnoticed?  Curious...
>>    
>>
>
>Yes, the new functions returns value in function parameter not result.
>
>Can you post me URL on the ALSA website, where this information is not 
>updated?
>
>						Jaroslav
>
>-----
>Jaroslav Kysela <perex@suse.cz>
>Linux Kernel Sound Maintainer
>ALSA Project, SuSE Labs
>
>
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