Issue building 6.14.08 with Pythia8

ROOT
1

_ROOT Version: 6.14.08
_Platform: Ubuntu 18.04
_Compiler: gcc version 7.3.0

Dear Rooters,
I CMade root6 with Pythia8 enabled and get:

...
[ 94%] Linking CXX shared library ../../lib/libEGPythia8.so
/software/opt/bionic/x86_64/pythia8/8.235/lib/libpythia8.a(PartonDistributions.o):
In function `Pythia8::LHAPDF::symbol(std::__cxx11::basic_string<char, 
std::char_traits<char>, std::allocator<char> >)':
PartonDistributions.cc:(.text+0xb718): undefined reference to `dlsym'
...

I could solve this by adding “ldl” by hand to the linker command in:
montecarlo/pythia8/CMakeFiles/EGPythia8.dir/link.txt
I made Pythia8 with shared lib enabled an the .so was there.

Did I miss something?

Cheers
Otto

2

Hi Otto,

did you by chance upgrade your compiler recently and configured ROOT in the past with another gcc version?
Did you try to scratch the build directory and re-configure and re-build?

Cheers,
D

3

HI Danilo,
thanks for the advice,
I redid from scratch and it works.

The only thing I can think of why it failed first time:
I made Pythia8 without the option: enable-shared,
after getting the before mentioned link error I remade
with the option enable-shared.
I however did the CMake config step again but may be
this wasnt enough.

Cheers
Otto