Support #2713
openProbably a linking error
0%
Description
Ive been playing around a bit with Wt now, but ever so often I encounter this silly little problem, and Im not certain where the error stems from:
Undefined symbols for architecture x86_64:
"Wt::WLink::WLink(Wt::WLink::Type, std::string const&)", referenced from:
ControlExample::page1() in ControlSkeleton.o
"Wt::WObject::setObjectName(std::string const&)", referenced from:
vtable for ControlExample in ControlSkeleton.o
"Wt::WString::WString(std::string const&, Wt::CharEncoding)", referenced from:
ControlExample::ControlExample(Wt::WEnvironment const&) in ControlSkeleton.o
ControlExample::header() in ControlSkeleton.o
"Wt::WApplication::makeAbsoluteUrl(std::string const&) const", referenced from:
vtable for ControlExample in ControlSkeleton.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: * [ControlSkeleton] Error 1
Both my Boost and my Wt install are done to custom folders, so I had to run: export DYLD_LIBRARY_PATH=/custom/directory/lib:$DYLD_LIBRARY_PATH for Boost. I did not do this for Wt, but I have added DYLD_LIBRARY_PATH to my Run environment in Qt Creator. And Ive added the LIBS -lwt -lwthttp -lboost_signals (including their paths) to my *.pro file. I wonder if I lack some libraries in my LIBS settings, and Ive searched for what libraries the functions are dependent on, but I would not be surprised if someone provide me a link to a site I most definitively should have looked at. Im running this on my MacBook. Earlier today I ran the same program on my Raspberry Pi, no problems at all.... its so strange. Im trying to find somewhere I can see what DYLD_LIBRARY_PATH's are set on this MacBook, so if anyone knows..
Updated by Koen Deforche about 11 years ago
- Status changed from New to Feedback
- Assignee set to Koen Deforche
Hey,
I can pinpoint it like that. It will help to see the actual link command:
VERBOSE=1 make
A mac usually has an empty DYLD_LIBRARY_PATH by default, in my experience. You can check with
echo $DYLD_LIBRARY_PATH
But it's important to understand that this path is not involved in the linking problem. Linking ignores the DYLD_LIBRARY_PATH; only running an application may consult this path.
Regards,
koen
Updated by Tor Arne Fallingen about 11 years ago
Hey koen.
Im not sure I follow, but I think you want to see more of the make commands? Well, I copied the whole thing from the compile output. It was not like a million miles long. Im using Qt Creator.
22:08:19: Starting: "/usr/bin/make"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -headerpad_max_install_names -Wl,-syslibroot,/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk -mmacosx-version-min=10.6 -o ControlSkeleton main.o -F/Users/taf/Qt5.2.1/5.2.1/clang_64/lib -L/Users/taf/Wt/lib -lwt -lwthttp -L/Users/taf/Boost/lib -lboost_signals -lboost_system -lboost_thread -lboost_filesystem -lboost_regex -framework QtCore
Undefined symbols for architecture x86_64:
"Wt::WLink::WLink(Wt::WLink::Type, std::string const&)", referenced from:
ControlSkeleton::page1() in main.o
"Wt::WObject::setObjectName(std::string const&)", referenced from:
vtable for ControlSkeleton in main.o
"Wt::WString::WString(std::string const&, Wt::CharEncoding)", referenced from:
ControlSkeleton::ControlSkeleton(Wt::WEnvironment const&) in main.o
ControlSkeleton::header() in main.o
"Wt::WApplication::makeAbsoluteUrl(std::string const&) const", referenced from:
vtable for ControlSkeleton in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: * [ControlSkeleton] Error 1
22:08:20: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project ControlSkeleton (kit: Desktop Qt 5.2.1 clang 64bit)
When executing step 'Make'
22:08:20: Elapsed time: 00:01.
Then if I understand you correctly, $DYLD_LIBRARY_PATH is one single entry (one path) and its temporary? Because yes I tried the "echo $DYLD_LIBRARY_PATH", and that gives me nada. And since I installed both Boost and Wt in custom locations, I need to link both the lib and the include directories manually when I use something dependent on them. Is there a way to do this more permanent? Like entering a path in a system file to include in the systems default directories to look for libraries and such? I feel green when I ask these things, but Im learning, and setting up RPi 50-100 times surely helps in starting to understand a little more how things are working.
Updated by Koen Deforche about 11 years ago
Hey,
The reason may be that you haven't built Wt the library with the same toolchain as your application:
- gcc versus clang
- libc versus stdlibc
- C+11 versus C+98
On MacOSX, the toolchains are a bit in a state of flux (moving away from gcc, towards CLang) but that requires some attention when trying to build applications and libraries.
Regards,
koen