Many thanks to Brian for his very useful information and help. A quick look at mgcv package already gives me some directions to try. I remember that I tried to use Rlapack.dll instead of R.dll without success, perhaps because I don't know how to build an import library for Rlapack.dll and link against it (README.packages shows how to do this for R.dll using R.exp, but I could not find Rlapack.exp). I will try to see if I can figure out this part using VC++6.0.
Yes, I am still using R-2.2.1. I did try to upgrade it to R-2.4.1. However, the newer versions cause some troubles for my C programs. They produce error messages when my DLL are loaded into R. The problem relates to function calls such as isfinite. I haven't figured out why my C programs have this problem with newer versions of R but not with version 2.2.1. I remember there was a post on this issue in this list, but I did not see any solution. I hope to find a clue about it too so that I can keep the pace of R development. Paul. ----- Original Message ----- From: Prof Brian Ripley <[EMAIL PROTECTED]> Date: Friday, March 30, 2007 1:56 am Subject: Re: [R] Using functions in LAPACK in a C program To: Paul August <[EMAIL PROTECTED]> Cc: r-help@stat.math.ethz.ch > On Thu, 29 Mar 2007, Paul August wrote: > > > Hi, > > > > I wonder where I can find an example of using a function in > LAPACK > > library in a user's own C code. > > In about 20 R packages, e.g. the recommended package mgcv. > > > I wrote a C program which will be > > compiled and linked to produce a DLL file and then loaded into > R. I hope > > to use a function from LAPACK library, for example, dgesdd, in > the > > program. Following R manual, I call the function by > F77_CALL(dgesdd) in > > the program. The program can be compiled without problems. > However, when > > it is linked to produce a DLL file, I get an error message > > > > Test.obj : error LNK2001: unresolved external symbol _dgesdd_ > > Test.dll : fatal error LNK1120: 1 unresolved externals > > > > I use VC++6.0 and the command of linking is something like this > > > > link.exe Rdll.lib /nologo /dll /out:Test.dll > /libpath:C:\R\R-2.2.1\src\gnuwin32 Test.obj > > > > Apparently, the linker cannot resolve dgesdd from Rdll.lib. If > anyone > > knows what I missed here or any example that shows how this > can be done > > properly, please let me know. Thanks a lot. > > It is in Rlapack.dll not R.dll. > > The linking information is in 'Writing R Extensions' for those > using the > recommended compilation system (search for LAPACK_LIBS). > > You will need to build an import library for Rlapack.dll and > link against > that. > > And BTW you seem to be using R 2.2.1: please update as we can > only offer > accurate advice on recent systems. > > -- > Brian D. > Ripley, [EMAIL PROTECTED] > Professor of Applied Statistics, > http://www.stats.ox.ac.uk/~ripley/University of > Oxford, Tel: +44 1865 272861 (self) > 1 South Parks > Road, +44 1865 272866 (PA) > Oxford OX1 3TG, > UK Fax: +44 1865 272595 > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R- > project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ----------------------------------------------- Dr. Paul Y. Peng Associate Professor of Biostatistics Department of Community Health and Epidemiology and Department of Mathematics and Statistics Queen's University, Kingston, ON, K7L 3N6 Phone: 613-533-6000 Ext 78525 Email: [EMAIL PROTECTED] Fax: 613-533-6794 ----------------------------------------------- [[alternative HTML version deleted]]
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