[Rcpp-devel] On Developing Header Packages

This is probably the best place I can think of to ask this question if
perhaps not completely on topic.  Some quick context:

I am exploring GPGPU computing and with my 'open-source' mindset I quickly
gravitated to using OpenCL.  Thankfully, many wonderful programmers have
already begun creating libraries to make this language better and faster.
One such library is the clBLAS library which essentially implements BLAS
routines for OpenCL enabled devices. Naturally, I would like to use this
library but I don't like the idea of telling users to install a dependency
outside of R and would rather have them install another package.  Therefore,
I have it in my head to create a header package for the clBLAS library to be
used by anyone exploring OpenCL programming within R.

This leads me to my two general questions that I hope others can comment.

1.  What are developers thoughts regarding the 'packaging' of various C++
header libraries?  I know this has be very successfully done with the 'BH'
package but is this considered an exception or an example?

2. If it is encouraged to create such header packages are there any
guidelines or standards that should be followed?  Is there an expected
structure?  I can look at the 'BH' package and go from there but it would be
nice if the R(cpp) community had some collective opinion about this.

Regards,
Charles

Le 7 avr. 2015 ? 20:51, JJ Allaire <jj.allaire at gmail.com> a ?crit :

I think that header-only packages (where possible) are definitely
preferable within the R package ecosystem because it allows you to
sidestep a lot of build configuration and runtime linking complexity.

The rub is that some libraries simply can't be made header-only,
especially if they make use of static data. I was able to convert the
TinyThread library to header-only by simply prefacing all
function/method definitions with the inline keyword. However that was
a pretty small library so I'm not sure you'd have the same easy time
of it with a larger library like clBLAS.

On Tue, Apr 7, 2015 at 2:37 PM, Charles Determan <cdetermanjr at gmail.com> wrote:
This is probably the best place I can think of to ask this question if
perhaps not completely on topic.  Some quick context:

I am exploring GPGPU computing and with my 'open-source' mindset I quickly
gravitated to using OpenCL.  Thankfully, many wonderful programmers have
already begun creating libraries to make this language better and faster.
One such library is the clBLAS library which essentially implements BLAS
routines for OpenCL enabled devices. Naturally, I would like to use this
library but I don't like the idea of telling users to install a dependency
outside of R and would rather have them install another package.  Therefore,
I have it in my head to create a header package for the clBLAS library to be
used by anyone exploring OpenCL programming within R.

This leads me to my two general questions that I hope others can comment.

1.  What are developers thoughts regarding the 'packaging' of various C++
header libraries?  I know this has be very successfully done with the 'BH'
package but is this considered an exception or an example?

2. If it is encouraged to create such header packages are there any
guidelines or standards that should be followed?  Is there an expected
structure?  I can look at the 'BH' package and go from there but it would be
nice if the R(cpp) community had some collective opinion about this.

Regards,
Charles