Unresolved symbols linking static libraries

Question

I a m getting some undefined references with the linking of static and dynamic libraries.

My goal is to get an executable with poco and uiohook libraries statically linked. In order to specify the static linking, I provide the direct path to the library, some as path/libName.a.

The following command:

/home/lrleon/LLVM-3.7/bin/clang -o collector -g -O2 -fno-strict-aliasing \
collector.o common-vars.o collector-events.o listeners.o \
active_window.o ../lib/libperfq-common.a \
/home/lrleon/aleph-w/libAleph.a /home/lrleon/poco/lib/libPocoNet.a \
/home/lrleon/poco/lib/libPocoFoundation.a /home/lrleon/uiohook/lib/libuiohook.a \
-lstdc++ -lX11 -lcairo -lgsl -lgslcblas -lpthread -lc 

Gives me the following errors:

/home/lrleon/poco/lib/libPocoFoundation.a(DateTime.o):DateTime.cpp:function Poco::DateTime::dayOfWeek() const: error: undefined reference to 'floor'
/home/lrleon/poco/lib/libPocoFoundation.a(DateTime.o):DateTime.cpp:function Poco::DateTime::toJulianDay(int, int, int, int, int, int, int, int): error: undefined reference to 'floor'
/home/lrleon/poco/lib/libPocoFoundation.a(DateTime.o):DateTime.cpp:function Poco::DateTime::toJulianDay(int, int, int, int, int, int, int, int): error: undefined reference to 'floor'
/home/lrleon/poco/lib/libPocoFoundation.a(DateTime.o):DateTime.cpp:function Poco::DateTime::toJulianDay(int, int, int, int, int, int, int, int): error: undefined reference to 'floor'
/home/lrleon/poco/lib/libPocoFoundation.a(NumericString.o):NumericString.cpp:function double_conversion::PowersOfTenCache::GetCachedPowerForBinaryExponentRange(int, int, double_conversion::DiyFp*, int*): error: undefined reference to 'ceil'
/home/lrleon/poco/lib/libPocoFoundation.a(NumericString.o):NumericString.cpp:function double_conversion::BignumDtoa(double, double_conversion::BignumDtoaMode, int, double_conversion::Vector<char>, int*, int*): error: undefined reference to 'ceil'
/home/lrleon/poco/lib/libPocoFoundation.a(NumericString.o):NumericString.cpp:function Poco::floatToStr(std::string&, float, int, int, char, char): error: undefined reference to 'floorf'
src/x11/input_hook.c:673: error: undefined reference to 'XRecordFreeData'
src/x11/input_hook.c:722: error: undefined reference to 'XRecordQueryVersion'
src/x11/input_hook.c:733: error: undefined reference to 'XRecordAllocRange'
src/x11/input_hook.c:745: error: undefined reference to 'XRecordCreateContext'
src/x11/input_hook.c:792: error: undefined reference to 'XRecordEnableContext'
src/x11/input_hook.c:812: error: undefined reference to 'XRecordFreeContext'
src/x11/input_hook.c:883: error: undefined reference to 'XRecordGetContext'
src/x11/input_hook.c:885: error: undefined reference to 'XRecordDisableContext'
src/x11/system_properties.c:134: error: undefined reference to 'XineramaIsActive'
src/x11/system_properties.c:136: error: undefined reference to 'XineramaQueryScreens'
src/x11/system_properties.c:396: error: undefined reference to 'XtGetMultiClickTime'
src/x11/system_properties.c:480: error: undefined reference to 'XtToolkitInitialize'
src/x11/system_properties.c:481: error: undefined reference to 'XtCreateApplicationContext'
src/x11/system_properties.c:485: error: undefined reference to 'XtOpenDisplay'
src/x11/system_properties.c:502: error: undefined reference to 'XtCloseDisplay'
src/x11/system_properties.c:503: error: undefined reference to 'XtDestroyApplicationContext'
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I do not understand why some symbols are not found. For example, ceil, floor are referenced by poco libraries, but these symbols would belong to c standard library. As I understand, these symbols should be resoluble because the c library is linked just at the end; that is after the poco libraries. Analogously with the references to X11 symbols which I believe are referenced with libuiohook and the linking order -lX11 is given afterward

Any idea about what am I doing wrong? Thanks in advance

Answer 1

The floor and ceil functions are defined in the Math library and I don't see you linking with libm by using -lm flag