Because the variable isn’t odr-used. You have a constexpr if there that always discards the branch that could use it. One of the points of constexpr if is that the discarded branch need not even compile, only be well-formed. That’s how we can place calls to non-existing member functions in a discarded branch.
In in order to link libm you need to add -lm argument, as this document; MPI under Linux in the Math Department says: If your code includes mathematical functions (like exp, cos, etc.), you need to link to the mathematics library libm.so. This is done, just like for serial compiling, by adding -lm to the … Read more
If Obstacle is an abstract base class, then make sure you declare all its virtual methods “pure virtual”: virtual void Method() = 0; The = 0 tells the compiler that this method must be overridden by a derived class, and might not have its own implementation. If the class contains any non-pure virtual functions, then … Read more
In Target > Build Settings: Look for Search Paths > Framework Search Paths, delete all paths which you have been warned; then in Library Search Paths, delete all paths which you have been warned.
Your distro configured gcc with –enable-default-pie, so it’s making position-independent executables by default, (allowing for ASLR of the executable as well as libraries). Most distros are doing that, these days. You actually are making a shared object: PIE executables are sort of a hack using a shared object with an entry-point. The dynamic linker already … Read more
You’re not doing anything wrong. I’m pretty sure google has not yet provided a arm64 version of their libGoogleAnalyticsServices.a, which is really annoying …it has been weeks since the public the release of Xcode 5GM. For now, I guess only build for armv7, armv7s or remove google analytics until they get their head out of … Read more
If you run g++ with the -v flag, you’ll see the link line it uses. Here’s a simple example program: #include <iostream> int main(void) { std::cout << “Hello, world!” << std::endl; return 0; } And the output from running g++ -v -o example example.cpp: Using built-in specs. Target: x86_64-linux-gnu Configured with: ../src/configure -v –with-pkgversion=’Ubuntu/Linaro 4.4.4-14ubuntu5.1′ … Read more
Normally this sort of failure happens when compiling your C++ code by invoking the C front-end. The gcc you execute understands and compiles the file as C++, but doesn’t link it with the C++ libraries. Example: $ gcc example.cpp Undefined symbols for architecture x86_64: “std::cout”, referenced from: _main in ccLTUBHJ.o “std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> … Read more
Follow the instructions here. It doesn’t require you to add any files to compile sources. I first missed that “Symbols Hidden by Default=NO” should be for your app target, not test target. It worked for me anyway ™.
I think you are confused about how the compiler puts things together. When you use -c flag, i.e. no linking is done, the input is C++ code, and the output is object code. The .o files thus don’t mix with -c, and compiler warns you about that. Symbols from object file are not moved to … Read more