C++ errors while compiling

Question

I am trying to compile a game, but getting 100+ errors like:

C:\Users\AppData\Local\Temp\cctQCagR.o: In function `load_image(std::string)': main.cpp:(.text+0x4bd4): undefined reference to `std::string::c_str() const' C:\Users\Bill\AppData\Local\Temp\cctQCagR.o: In function `createShip(float, float)': main.cpp:(.text+0x4da4): undefined reference to `std::allocator<char>::allocator()' main.cpp:(.text+0x4dbc): undefined reference to `std::basic_string<char, std::char_tra its<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> cons t&)' main.cpp:(.text+0x4de4): undefined reference to `std::basic_string<char, std::char_tra its<char>, std::allocator<char> >::~basic_string()' main.cpp:(.text+0x4e04): undefined reference to `std::basic_string<char, std::char_tra its<char>, std::allocator<char> >::~basic_string()' main.cpp:(.text+0x4e1c): undefined reference to `std::allocator<char>::~allocator()' main.cpp:(.text+0x4e28): undefined reference to `std::allocator<char>::allocator()' main.cpp:(.text+0x4e40): undefined reference to `std::basic_string<char, std::char_tra its<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> cons t&)' main.cpp:(.text+0x4e60): undefined reference to `std::allocator<char>::~allocator()' main.cpp:(.text+0x4e70): undefined reference to `__cxa_end_cleanup' main.cpp:(.text+0x4e98): undefined reference to `std::basic_string<char, std::char_tra its<char>, std::allocator<char> >::~basic_string()' main.cpp:(.text+0x4eb8): undefined reference to `std::basic_string<char, std::char_tra its<char>, std::allocator<char> >::~basic_string()' main.cpp:(.text+0x4ed0): undefined reference to `std::allocator<char>::~allocator()' main.cpp:(.text+0x4ef4): undefined reference to `std::allocator<char>::~allocator()' main.cpp:(.text+0x4f04): undefined reference to `__cxa_end_cleanup' C:\Users\Bill\AppData\Local\Temp\cctQCagR.o: In function `load_files()': main.cpp:(.text+0x5164): undefined reference to `std::allocator<char>::allocator()' main.cpp:(.text+0x517c): undefined reference to `std::basic_string<char, std::char_tra its<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> cons t&)' 

Answer 1

I believe you're trying to compile main.cpp with gcc instead of g++.

#include <string> #include <stdio.h> int main() {     std::string bla;     bla = "BLA BLA";     printf("%s\n",bla.c_str());     return 0; } 

If you build the above code snippet with gcc you get the errors you mention. If you use g++ it build ok, this makes sense since g++ will make sure all the proper stuff it put together when build C++.

Answer 2

You need to link your binary with libstdc++. You need to explicitly specify it in command line if using gcc:

gcc -lstdc++ tmp.cpp 

If using g++, libstdc++ will be linked by default:

g++ tmp.cpp