[Rd] Problem with compiling shared C/C++ library for loading into R (Linux)

[Samsiddhi Bhattacharjee]

   Thanks. I figured out the problem finally. The first error I
mentioned was solved by compiling
the external library blitz++ using the configure option --with-pic (or
compiler flag -fPIC). It has something to do with position indepent
code and global variables, which I frankly don't understand. Maybe
somebody can explain...

      The second one (undefined symbol: _ZSt4cerr) was because cerr is
a c++ object, and I was doing
"R CMD SHLIB" on the compiled object files, so it was linkiing using
gcc. Changing the linker to g++ (using
cpp source code during linking) works...or as suggested in a previous
post using -lstdc++ with gcc also works.

--Samsiddhi Bhattacharjee


On Sun, Jan 11, 2009 at 7:58 AM, torpedo fisken <torpedofisken at gmail.com> wrote:
> I think you're not linking it together when you call R CMD SHLIB, use
> something like
>
> R CMD SHLIB mylib.c yourlib1.o yourlib2.o
>
> Otherwise mail again with your Makefile, or all the commands you are using
>
> good luck
>
> 2009/1/11 Samsiddhi Bhattacharjee <samsiddhi.bhattacharjee at gmail.com>:
>> Dear all,
>>
>> I am using the .Call interface to call c++ code from R. For that, I am
>> trying to create a dynamic library (mylib.so)
>> using "R CMD SHLIB" by linking my own c++ code and an external c++
>> library (blitz++).
>>
>> The makefile works fine on my Mac, produces mylib.so and I am able to
>> call .Call() from R,  but on a linux
>> server (I think Debian),  I got the following error:
>>
>> ----------
>> /usr/bin/ld: /somepath/blitz/lib/libblitz.a(globals.o):
>> relocation R_X86_64_32 against `a local symbol' can not be used when
>> making a shared object; recompile with -fPIC
>> /somepath/blitz/lib/libblitz.a: could not read symbols: Bad value
>> collect2: ld returned 1 exit status
>> ----------
>>
>> I tried recompiling the blitz++ library with the -fPIC flag, and then
>> linking using -fPIC, it went thorugh without error
>> producing a "mylib.so" file.  But when I tried "dyn.load(mylib.so)"
>> from R, I got the error:
>>
>> ----------
>> Error in dyn.load("mylib.so") :
>>  unable to load shared library '/somepath/mylib.so':
>>  /somepath/mylib.so: undefined symbol: _ZSt4cerr
>> ---------
>>
>> I will really appreciate any help or advice on this problem.
>>
>> --Samsiddhi Bhattacharjee
>>
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>