compiling C code using headers from another R package

On Mar 12, 2013, at 3:35 PM, Herv? Pag?s wrote:

On 03/12/2013 11:56 AM, Simon Urbanek wrote:

On Mar 12, 2013, at 2:48 PM, Herv? Pag?s wrote:

On 03/12/2013 11:09 AM, Simon Urbanek wrote:

On Mar 12, 2013, at 2:01 PM, Herv? Pag?s wrote:

Hi,

On 03/12/2013 09:55 AM, Simon Urbanek wrote:

On Mar 12, 2013, at 12:30 PM, Kevin Horan wrote:

    Thanks for your input. To clarify, I don't need to use any part of GSL in my R code, nor do I wish to make any part of it accessible to users of eiR. I need it to compile other C/C++ code (LSH KIT), which I did not write, that will itself be used in eiR.
    My goal is allow the user to install eiR without also having to install GSL before hand.

If your package is on CRAN they won't need to as we are providing Mac and Windows binaries.

I think that at least on Windows, the user would still need to have the
GSL installed on his/her machine.

Why?

Linux can get the binaries form their distro, so the dependencies are installed automatically.

The target audience is people in bioinformatics who may not how to install something like GSL. It seems like what I was suggesting is not such a good idea, if it will be hard to reliably find the header files from another R package. I could also push all of GSL into eiR, but as GSL has over 5000 files, this makes the package very large ( >22 MB) and  slow to compile. Both of which are a problem when submitting a package to bioconductor. It may very well be that leaving GSL as an external dependency to eiR is really the best and easiest way, but I just wanted to see if there was any way to make it easier for the user.

Can you clarify what you mean by "user"? The vast majority of R users use binaries, so all this is irrelevant to them as they don't need to install GSL at all.

FWIW we currently have 7 or 8 Bioconductor packages that require the
GSL as an external system lib. That's because even if we provide Windows
binaries for those packages, those binaries are dynamically linked.
Is there a way to build those binaries that would avoid that dependency?

Yes, use static libgsl.

Ah yes, of course. Thanks for the reminder. Just checked with Dan and
turns out that we are using that libgsl.a too (made by Brian D. Ripley)
on our build system. Some Bioconductor packages have README or INSTALL
files that still mention that the Windows user needs to install the GSL
but that doesn't seem to be the case so we'll make sure this information
gets updated.

Also the SystemRequirements field in the DESCRIPTION file can be a
little bit confusing as it suggests that everybody requires the stuff
listed here when it actually depends whether the user is installing the
binary or not and how the binary was made.

Anyway, to answer Kevin's original question:

  how do I know where the GSL library and header files, packaged
  in GSLR, would live so I can point the compiler at them?

Use the LinkingTo field.

No, you're not linking to another package, your'e linking to a *library*. LinkingTo uses R's own mechanism for symbol detection in another *package*. I know, the name is a bit misleading but those are two different things.

I understand that but that's what Kevin wants right, i.e. linking
to another package.

No (you cannot link to another package - that's the misnomer), he wants to link to a library provided by another package (see his e-mail, he's asking about how to locate the GSL library supplied with RGSL, not to RGSL itself).

Maybe I misunderstand what the OP wants to do, and the only way to know
would be for him to clarify, but IIUC the RGSL package would only
contain the GSL library. At least that's how I understand it (and
that's what makes sense to me). So the RGSL package would contain
only 1 shared object (or 1 shared object per sub-arch): the GSLR.so
file (extension may vary). So I'm not sure what's the difference between
linking to the "GSL library supplied with RGSL" and linking to
"RGSL itself"?

GSL library inside RGSL is libgsl.* (where * is a, dylib, so, dll depending on the type and OS). This is *not* the same as RGSL.so/dll which would be the package shared object compiled by R for the package. There is a big difference: the shared objects that R creates for packages cannot be linked to, they are meant to be used with dlopen()/dlsym() - which is what R uses to load symbols entry points. That is also the reason why using LinkingTo: requires explicit exposure of symbols by the package providing the symbols as well as explicit loading of the symbols by the package that uses them. This is entirely different than linking to a library - in the latter case the linker (not R) establishes the connection between the symbols in the library and references - and in case of a static library they get copied into the binary that is being created (which is why you don't need it anymore after linking).

Cheers,
Simon

Very confusing to me. Thanks for your time and sorry if I'm missing something obvious.

H.

Yes there is the extra difficulty to register all the C functions in the GSL API (as pointed out by Dirk) but that's another story.

That's not another story - that's very much part of the story why using LinkingTo is not a good idea.

Cheers,
Simon

Thanks,
H.

Cheers,
Simon

Cheers,
H.

Cheers,
Simon

So, any other suggestions about how this could be accomplished?  Thanks.

Kevin

On 03/12/2013 05:26 AM, Simon Urbanek wrote:

Kevin,

On Mar 11, 2013, at 5:20 PM, Kevin Horan wrote:

I am developing an R package, eiR,  which depends on another C library, GNU scientific library (GSL). In order to make life easier for the user, it would be nice to not have this as an external dependency, thus I would like to wrap this library in another R package, say GSLR for example. Thus far I know how to do this. The C code in eiR requires the .so library and the header files from GSL in order to compile. So the idea is that eiR would depend on GSLR, then GSLR gets compiled and installed first, then, while eiR is installing, it should be able to make use of the GSL library and header files while compiling. So my question is, how do I know where the GSL library and header files, packaged in GSLR, would live so I can point the compiler at them? I know how to find the installed directory of an R package from within R, but is there way to find that out using just Makevars or a Makefile? I'm open to suggestions about a better way organize all of this as well. I li

t

he

!

   idea of keeping the GSL code separate so that it can be updated/changed independently from eiR though.

Have a look at Rcpp.

    I'm also aware of the gsl R library on CRAN, however, this just wraps GSL in R functions, but I need to use the GSL C functions in other C code in eiR.

Why is what you are proposing any better than simply using GSL in eiR? You will still need the GSL external dependency for GSLR and you are only adding a lot of complexity by linking into another package's external directory (you cannot use libs) which is in itself very tricky (you'll have to deal with both static and shared version, multi-arch setups, possible relocation etc.). It won't make it any easier on the user, rather to the contrary as there will be more things to break. The only reason Rcpp goes into such length to do this is because it has no choice (the Rcpp library has to use the same libR so cannot be used as external dependency) - I would certainly not recommend it for something as trivial as providing GSL.

Cheers,
Simon

Thanks.

Kevin

--
Herv? Pag?s

Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024

E-mail: hpages at fhcrc.org
Phone:  (206) 667-5791
Fax:    (206) 667-1319

--
Herv? Pag?s

Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024

E-mail: hpages at fhcrc.org
Phone:  (206) 667-5791
Fax:    (206) 667-1319

--
Herv? Pag?s

Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024

E-mail: hpages at fhcrc.org
Phone:  (206) 667-5791
Fax:    (206) 667-1319