Linker Error with log4cxx

Question

I'd like to use Apache log4cxx and am running into a problem. I'm running on Debian 8 and installed log4cxx using

apt-get install liblog4cxx10-dev

I have embedded one of the code snippets in the Documentation Page into the code below:

#include <log4cxx/logger.h>
#include <math.h>

int main(int argc, char* argv[]) {
    log4cxx::LoggerPtr logger(log4cxx::Logger::getLogger("com.foo"));
    int i = 10;
    const char* region = "World";

    LOG4CXX_INFO(logger, "Simple message text.")
    LOG4CXX_INFO(logger, "Hello, " << region)
    LOG4CXX_DEBUG(logger, L"Iteration " << i)
    LOG4CXX_DEBUG(logger, "e^10 = " << std::scientific << exp(10.0))
    LOG4CXX_WARN(logger, L"" << i << L" is the number of the iteration.")

    return 0;
}

When compiling with Eclipse CDT (gcc 5.3.0 built from source) I get the following linker errors:

make all 
Building file: ../src/tester.cxx
Invoking: GCC C++ Compiler
g++ -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/tester.d" -MT"src/tester.o" -o "src/tester.o" "../src/tester.cxx"
Finished building: ../src/tester.cxx

Building target: logtest
Invoking: GCC C++ Linker
g++ -L/usr/lib/x86_64-linux-gnu -o "logtest"  ./src/tester.o   -llog4cxx
./src/tester.o: In function `main':
/home/andand/workspace/logtest/Debug/../src/tester.cxx:9: undefined reference to `log4cxx::helpers::MessageBuffer::str[abi:cxx11](log4cxx::helpers::CharMessageBuffer&)'
/home/andand/workspace/logtest/Debug/../src/tester.cxx:9: undefined reference to `log4cxx::Logger::forcedLog(log4cxx::helpers::ObjectPtrT<log4cxx::Level> const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, log4cxx::spi::LocationInfo const&) const'
/home/andand/workspace/logtest/Debug/../src/tester.cxx:10: undefined reference to `log4cxx::helpers::MessageBuffer::str[abi:cxx11](log4cxx::helpers::CharMessageBuffer&)'
/home/andand/workspace/logtest/Debug/../src/tester.cxx:10: undefined reference to `log4cxx::Logger::forcedLog(log4cxx::helpers::ObjectPtrT<log4cxx::Level> const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, log4cxx::spi::LocationInfo const&) const'
/home/andand/workspace/logtest/Debug/../src/tester.cxx:11: undefined reference to `log4cxx::helpers::MessageBuffer::str[abi:cxx11](std::basic_ostream<wchar_t, std::char_traits<wchar_t> >&)'
/home/andand/workspace/logtest/Debug/../src/tester.cxx:11: undefined reference to `log4cxx::Logger::forcedLog(log4cxx::helpers::ObjectPtrT<log4cxx::Level> const&, std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> > const&, log4cxx::spi::LocationInfo const&) const'
/home/andand/workspace/logtest/Debug/../src/tester.cxx:12: undefined reference to `log4cxx::helpers::MessageBuffer::str[abi:cxx11](std::ostream&)'
/home/andand/workspace/logtest/Debug/../src/tester.cxx:12: undefined reference to `log4cxx::Logger::forcedLog(log4cxx::helpers::ObjectPtrT<log4cxx::Level> const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, log4cxx::spi::LocationInfo const&) const'
/home/andand/workspace/logtest/Debug/../src/tester.cxx:13: undefined reference to `log4cxx::helpers::MessageBuffer::str[abi:cxx11](std::basic_ostream<wchar_t, std::char_traits<wchar_t> >&)'
makefile:45: recipe for target 'logtest' failed
/home/andand/workspace/logtest/Debug/../src/tester.cxx:13: undefined reference to `log4cxx::Logger::forcedLog(log4cxx::helpers::ObjectPtrT<log4cxx::Level> const&, std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> > const&, log4cxx::spi::LocationInfo const&) const'
collect2: error: ld returned 1 exit status
make: *** [logtest] Error 1

I double checked where apt installed the libraries:

root@starsim-dev:/home/andand# find / -name *log4cxx*
/usr/lib/x86_64-linux-gnu/liblog4cxx.a
/usr/lib/x86_64-linux-gnu/liblog4cxx.so.10.0.0
/usr/lib/x86_64-linux-gnu/liblog4cxx.so.10
/usr/lib/x86_64-linux-gnu/liblog4cxx.so
/usr/lib/x86_64-linux-gnu/pkgconfig/liblog4cxx.pc
/usr/include/log4cxx
/usr/include/log4cxx/private/log4cxx_private.h
/usr/include/log4cxx/log4cxx.h
/usr/share/doc/liblog4cxx10
/usr/share/doc/liblog4cxx10-dev
/usr/share/lintian/overrides/liblog4cxx10
/usr/share/lintian/overrides/liblog4cxx10-dev
/var/cache/apt/archives/liblog4cxx10-dev_0.10.0-4_amd64.deb
/var/cache/apt/archives/liblog4cxx10_0.10.0-4_amd64.deb
/var/lib/dpkg/info/liblog4cxx10:amd64.postinst
/var/lib/dpkg/info/liblog4cxx10:amd64.shlibs
/var/lib/dpkg/info/liblog4cxx10-dev.list
/var/lib/dpkg/info/liblog4cxx10:amd64.list
/var/lib/dpkg/info/liblog4cxx10:amd64.md5sums
/var/lib/dpkg/info/liblog4cxx10:amd64.postrm
/var/lib/dpkg/info/liblog4cxx10-dev.md5sums

The documentation on Apache's website isn't entirely clear what other library dependencies exist. Does anybody have some insight into what I'm missing?

did you ever figure out the issue about undefined reference to `log4cxx::Logger::forcedLog(log4cxx::helpers::ObjectPtrT — caot, Nov 01 '17 at 19:45
@caot No. I didn't need all of the features in log4cxx, so I just rolled my own to meet my needs, and that worked well enough. I may go back and try again, though. — andand, Nov 02 '17 at 03:16

rjhowell44 · Answer 1 · 2019-08-25T16:29:12.100

1

I ran into the same set of linker errors trying to use log4cxx on Ubuntu 18.04. I was able to get their code snippets to work - including the one above - by adding the following additional Apache libs to my MakeFile

LIBS+= -llog4cxx -laprutil-1 -lapr-1

Make sure to list them in the above order.

edited Aug 25 '19 at 16:29

answered Aug 24 '19 at 22:10

rjhowell44

23
4

please send a complete solution with enough description to understand what are you doing in your code and how the problem solved. – Mehdi Yeganeh Aug 24 '19 at 22:33
Updated answer above. I hope it helps – rjhowell44 Aug 25 '19 at 19:02
Thanks for the pointer. Turns out this is something which seems to have been fixed. I made a couple minor adjustments and it now compiles just fine, even without additional Apache libraries. – andand Aug 28 '19 at 01:27

Linker Error with log4cxx

1 Answers1