Hi, The whole pichture is the following:
You need to monitor the modify_counter value returned by SNDCTL_MIXERINFO. If it has changed then you need to read all controls and check if their value has changed. In this way you can detect if some other application has changed the values. Remember that the changes made by the application itself also increment modify_counter. MIXF_POLL indicates controls that reflect the outside world. They are likely to change their value at any moment. Peak meter controls can also change their value in this way even they don't have MIXF_POLL flag. ENUMINFO is usually static. However if the version field is != 0 then the value may change. The version field will then be incremented every time a change happens. Hannu --- 16.12.2010 22.43, o...@lilltiger.se wrote: > On Thu, 16 Dec 2010 22:24:18 +0200, Hannu Savolainen > <ha...@opensound.com> wrote: >> Hi, >> >> MIXF_POLL tells that the value may change when the state of the >> device >> changes. For this reason the application should check the value >> periodically (for example once per second) and to update the GUI if >> the >> value has changed. > > Again I ask, what does this imply, you pretty much quoted the > documentation but gave no explenation. > Is it only the value you get from "SNDCTL_MIX_READ" or can things like > "SNDCTL_MIX_ENUMINFO" also change. > >> >> Best regards, >> >> Hannu >> --- >> 16.12.2010 21.55, o...@lilltiger.se wrote: >>> The docs say that it indicates that the control can change >>> spontainiolusy but what does this imply. >>> >>> Let's say the control is an "MIXT_MUTE" then i presume it would >>> onlychnage if it's on or off. >>> So all one have to do is to read the value once a second and update >>> the >>> GUI control. >>> >>> But how does it change more advanced controls like "MIXT_ENUM", can >>> it >>> change the different options that is avaible, or just wich of the >>> options that is selected, or can it change both. >>> >>> Is there any guidelines to how it may change an control? >>> >>> / Lilltiger >>> _______________________________________________ >>> oss-devel mailing list >>> oss-devel@mailman.opensound.com >>> http://mailman.opensound.com/mailman/listinfo/oss-devel >> >> _______________________________________________ >> oss-devel mailing list >> oss-devel@mailman.opensound.com >> http://mailman.opensound.com/mailman/listinfo/oss-devel > > _______________________________________________ > oss-devel mailing list > oss-devel@mailman.opensound.com > http://mailman.opensound.com/mailman/listinfo/oss-devel _______________________________________________ oss-devel mailing list oss-devel@mailman.opensound.com http://mailman.opensound.com/mailman/listinfo/oss-devel
