My host computer is a x86 PC running Ubuntu 18 and have arm-linux-gnueabi-g++ and arm-linux-gnueabi-gcc suit installed. I had intended to cross-compiling and running a C++ project on my ARM (armv7l, Cortex-A17) device.
For ease of description of my problem, a testing project has been set with following three source files:
//global.hpp
class Global { public: Global();};
extern Global global;
//global.cpp
#include "global.hpp"
#include <iostream>
Global global;
Global::Global(){std::cout << "Global" << std::endl;}
//main.cpp
#include <iostream>
int main(int nArgCnt, char *ppArgs[]) {
std::cout << "main" << std::endl;
return 0;
}
And the build script "build.sh" is:
#!/bin/bash
arm-linux-gnueabi-g++ -c global.cpp -o global.o
arm-linux-gnueabi-ar qc libglobal.a global.o
arm-linux-gnueabi-g++ -static main.cpp libglobal.a -o main
After built done I push the executable "main" to device, running it got following result:
main
It seems that the constructor of Global not be called.
I have tried to directly link global.o into main, modified the build.sh to:
#!/bin/bash
arm-linux-gnueabi-g++ -c global.cpp -o global.o
arm-linux-gnueabi-g++ -static main.cpp global.o -o main
Then I got expected result:
Global
main
But this is just a tesing project, actually I have a more bigger project that have many sources and must be built with static linkage. How to make the constructor Global::Global() be called properly from libglobal.a ? Thank you for your help!
If I did the build with g++ and ar, the result is not expected also:
#!/bin/bash
g++ -c global.cpp -o global.o
ar qc libglobal.a global.o
g++ -static main.cpp libglobal.a -o main
./main
got
main
Finally, the question Why doesn't attribute((constructor)) work in a static library and it's solution did works.
