Hey hey,
I'd like to run Csound inside a c++ application using its API. Csound should 
communicate only through the host, not directly connecting to any outside 
audio/MIDI I/O. Sample buffer size will be dictated by a host set frame size.

In audio this is possible, on e can pass in sample buffers and read them. But 
how about control channel access? I see that the C function:
csoundSetControlChannel
takes a single value
and
csoundGetControlChannel
returns a single value.

Is there a way to read/write control data at the speed of the control rate in 
such a setup? We can assume that I set the control rate to work well with the 
frame buffer size of the audio.

Or is there another approach, when automating Csound k-rate values when 
running in such a way?

As an example, you can take JACK process callback function, which will process 
a fixed given number of audio samples per call and audio channel.

Any help is very much appreciated.

Best wishes,

Jeanette

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Thank you Michael! This is helpful. So I might look at the Csound7 API.

Just to be sure though: with Csound6 and that type of setup, I best send one 
control value per host processing callback.

Best wishes,

Jeanette

Michael Gogins, Oct 8 2026:

> In Csound 7, CsoundPerformanceThread provides a thread-safe, asynchronous
> FIFO queue for incoming control commands. The performance thread processes
> a batch of queued commands before calling csoundPerformKsmps() for each
> control period. Commands arriving after the current batch has been detached
> are generally processed in the next cycle. Applications that manage their
> own performance threads can implement equivalent queues in C++. For
> outgoing control data, the host can either poll Csound's named channels or
> else register an output-channel callback to receive values emitted by the
> outvalue opcode.
>
> Best,
> Mike
>
> -----------------------------------------------------
> Michael Gogins
> Irreducible Productions
> http://michaelgogins.tumblr.com
> Michael dot Gogins at gmail dot com
>
>
> On Thu, Oct 8, 2026 at 2:59 PM Jeanette C. <
> 000015cdd0ffa6cd-dmarc-request@listserv.heanet.ie> wrote:
>
>> Hey hey,
>> I'd like to run Csound inside a c++ application using its API. Csound
>> should
>> communicate only through the host, not directly connecting to any outside
>> audio/MIDI I/O. Sample buffer size will be dictated by a host set frame
>> size.
>>
>> In audio this is possible, on e can pass in sample buffers and read them.
>> But
>> how about control channel access? I see that the C function:
>> csoundSetControlChannel
>> takes a single value
>> and
>> csoundGetControlChannel
>> returns a single value.
>>
>> Is there a way to read/write control data at the speed of the control rate
>> in
>> such a setup? We can assume that I set the control rate to work well with
>> the
>> frame buffer size of the audio.
>>
>> Or is there another approach, when automating Csound k-rate values when
>> running in such a way?
>>
>> As an example, you can take JACK process callback function, which will
>> process
>> a fixed given number of audio samples per call and audio channel.
>>
>> Any help is very much appreciated.
>>
>> Best wishes,
>>
>> Jeanette
>>
>> --
>>   * PeerTube: https://makertube.net/@jeanette_c
>>   * GitHub: https://github.com/jeanette-c
>>   * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g
>>
>> Csound mailing list
>> Csound@listserv.heanet.ie
>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
>> Send bugs reports to
>>         https://github.com/csound/csound/issues
>> Discussions of bugs and features can be posted here
>>
>
> Csound mailing list
> Csound@listserv.heanet.ie
> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
> Send bugs reports to
>        https://github.com/csound/csound/issues
> Discussions of bugs and features can be posted here
>

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Hey hey,
I'd like to run Csound inside a c++ application using its API. Csound should communicate only through the host, not directly connecting to any outside audio/MIDI I/O. Sample buffer size will be dictated by a host set frame size.

In audio this is possible, on e can pass in sample buffers and read them. But how about control channel access? I see that the C function:
csoundSetControlChannel
takes a single value
and
csoundGetControlChannel
returns a single value.

Is there a way to read/write control data at the speed of the control rate in such a setup? We can assume that I set the control rate to work well with the frame buffer size of the audio.

Or is there another approach, when automating Csound k-rate values when running in such a way?

As an example, you can take JACK process callback function, which will process a fixed given number of audio samples per call and audio channel.

Any help is very much appreciated.

Best wishes,

Jeanette

--
* PeerTube: https://makertube.net/@jeanette_c
* GitHub: https://github.com/jeanette-c
* Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g

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Hello Iain,
thank you for that suggestion. I downloaded the sources and am looking at 
them. I think this might prove helpful in my undertaking. It will become 
clearer in time.

Best wishes,

Jeanette

Iain Duncan, Oct 9 2026:

> If you want another example, you might find the code for the Csound6~
> object in Max useful. It's a port of Victor's PD object with a bunch of
> extra bells and whistles, including control channel IO with Max. It's all
> done in plain C. I plan to update it when Csound7 is fully released.
>
> https://github.com/iainctduncan/csound_max
>
> iain
>
>
>
>
> On Thu, Oct 8, 2026 at 8:43 AM Victor Lazzarini <
> 000010b17ddd988e-dmarc-request@listserv.heanet.ie> wrote:
>
>> First step is to study the C++ examples in the repo
>>
>> https://github.com/csound/csoundAPI_examples
>>
>> they will give you a good idea of what you need to do for various use
>> cases.
>>
>> Prof. Victor Lazzarini
>> Maynooth University
>> Ireland
>>
>> On 8 Oct 2026, at 14:00, Jeanette C. <
>> 000015cdd0ffa6cd-dmarc-request@listserv.heanet.ie> wrote:
>>
>> Hey hey,
>> I'd like to run Csound inside a c++ application using its API. Csound
>> should communicate only through the host, not directly connecting to any
>> outside audio/MIDI I/O. Sample buffer size will be dictated by a host set
>> frame size.
>>
>> In audio this is possible, on e can pass in sample buffers and read them.
>> But how about control channel access? I see that the C function:
>> csoundSetControlChannel
>> takes a single value
>> and
>> csoundGetControlChannel
>> returns a single value.
>>
>> Is there a way to read/write control data at the speed of the control rate
>> in such a setup? We can assume that I set the control rate to work well
>> with the frame buffer size of the audio.
>>
>> Or is there another approach, when automating Csound k-rate values when
>> running in such a way?
>>
>> As an example, you can take JACK process callback function, which will
>> process a fixed given number of audio samples per call and audio channel.
>>
>> Any help is very much appreciated.
>>
>> Best wishes,
>>
>> Jeanette
>>
>> --
>> * PeerTube: https://makertube.net/@jeanette_c
>> * GitHub: https://github.com/jeanette-c
>> * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g
>>
>> Csound mailing list
>> Csound@listserv.heanet.ie
>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
>> Send bugs reports to
>>       https://github.com/csound/csound/issues
>> Discussions of bugs and features can be posted here
>>
>> The information contained in this email may be confidential and
>> privileged. It is intended only for the addressee(s) stated above. If you
>> are not an addressee any use, dissemination, distribution, publication or
>> copying of the information contained in this email is strictly prohibited.
>> If you have received this email in error, please immediately notify us by
>> email at dataprotection@mu.ie and delete this email from your system.
>>
>> Please note that Maynooth University is subject to Freedom of Information
>> and Data Protection laws. We may be required to disclose the content of
>> emails under the* FOI Act 2014*, the* Data Protection Act 2018* or *GDPR*.
>>
>> Is don seolaí / do na seolaithe thuasluaite amháin an ríomhphost seo.
>> D’fhéadfadh an t-eolas atá ann a bheith rúnda agus faoi phribhléid. Mura
>> seolaí tú, tá cosc iomlán ar aon eolas atá sa ríomhphost seo a úsáid, a
>> scaipeadh, a dháileadh, a fhoilsiú nó a chóipeáil. Má fuair tú an
>> ríomhphost seo trí thimpiste, cuir sin in iúl dúinn láithreach trí
>> ríomhphost a chur chuig  dataprotection@mu.ie  agus scrios an ríomhphost
>> seo ó do chóras.
>>
>> Tabhair faoi deara go bhfuil Ollscoil Mhá Nuad faoi réir dhlíthe um
>> Shaoráil Faisnéise agus um Chosaint Sonraí. D’fhéadfadh ceangal a bheith
>> orainn ábhar ríomhphoist a nochtadh faoin *Acht um Shaoráil Faisnéise
>> 2014*, faoin *Acht um Chosaint Sonraí 2018* nó faoi *GDPR*.
>>
>> Registered charity number 20037130
>>
>>
>> Csound mailing list Csound@listserv.heanet.ie
>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to
>> https://github.com/csound/csound/issues Discussions of bugs and features
>> can be posted here
>
>
>
> -- 
> Iain Duncan
> Interdisciplinary PhD Candidate, Computer Science & Music
> University of Victoria, Canada
>
> Csound mailing list
> Csound@listserv.heanet.ie
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> Discussions of bugs and features can be posted here
>

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