yep, you're right, after some initial clean-up and running with or without
--as-cran R CMD check gives a NOTE
* checking compiled code
File ‘socketeer/libs/socketeer.so’:
Found non-API calls to R: ‘R_GetConnection’,
‘R_new_custom_connection’
Compiled code should not call non-API entry points in R.
See 'Writing portable packages' in the 'Writing R Extensions' manual.
Connections in general seem more useful than ad-hoc functions, though perhaps
for Frederick's use case Duncan's suggestion is sufficient. For non-CRAN
packages I personally would implement a connection.
(I mistakenly thought this was a more specialized mailing list; I wouldn't have
posted to R-devel on this topic otherwise)
Martin Morgan
On 5/6/20, 4:12 PM, "Gábor Csárdi" <csardi.ga...@gmail.com> wrote:
AFAIK that API is not allowed on CRAN. It triggers a NOTE or a
WARNING, and your package will not be published.
Gabor
On Wed, May 6, 2020 at 9:04 PM Martin Morgan <mtmorgan.b...@gmail.com>
wrote:
>
> The public connection API is defined in
>
> https://github.com/wch/r-source/blob/trunk/src/include/R_ext/Connections.h
>
> I'm not sure of a good pedagogic example; people who want to write their
own connections usually want to do so for complicated reasons!
>
> This is my own abandoned attempt
https://github.com/mtmorgan/socketeer/blob/b0a1448191fe5f79a3f09d1f939e1e235a22cf11/src/connection.c#L169-L192
where connection_local_client() is called from R and _connection_local()
creates and populates the appropriate structure. Probably I have done things
totally wrong (e.g., by not checking the version of the API, as advised in the
header file!)
>
> Martin Morgan
>
> On 5/6/20, 2:26 PM, "R-devel on behalf of Duncan Murdoch"
<r-devel-boun...@r-project.org on behalf of murdoch.dun...@gmail.com> wrote:
>
> On 06/05/2020 1:09 p.m., frede...@ofb.net wrote:
> > Dear R Devel,
> >
> > Since Linux moved away from using a file-system interface for
audio, I think it is necessary to write special libraries to interface with
audio hardware from various languages on Linux.
> >
> > In R, it seems like the appropriate datatype for a `snd_pcm_t`
handle pointing to an open ALSA source or sink would be a "connection".
Connection types are already defined in R for "file", "url", "pipe", "fifo",
"socketConnection", etc.
> >
> > Is there a tutorial or an example package where a new type of
connection is defined, so that I can see how to do this properly in a package?
> >
> > I can see from the R source that, for example, `do_gzfile` is
defined in `connections.c` and referenced in `names.c`. However, I thought I
should ask here first in case there is a better place to start, than trying to
copy this code.
> >
> > I only want an object that I can use `readBin` and `writeBin` on,
to read and write audio data using e.g. `snd_pcm_writei` which is part of the
`alsa-lib` package.
>
> I don't think R supports user-defined connections, but probably
writing
> readBin and writeBin equivalents specific to your library wouldn't be
> any harder than creating a connection. For those, you will probably
> want to work with an "external pointer" (see Writing R Extensions).
> Rcpp probably has support for these if you're working in C++.
>
> Duncan Murdoch
>
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