gnu compiler from the command line

Question

Im learning c++ and I compile from the command line. I have a problem when it comes to trying to add 3rd party libraries. I cant seam to figure out the linker system. Does anyone know a good tutorial or something like that?

For example I want to play around with the SDL2 library and ill use a command like this.

c++ -I/Library/Frameworks/SDL2.framework/Headers -L/Library/Frameworks/SDL2.framework/ -lSDL2 helloworld.cpp

and I get the error ld: library not found for -lSDL2

Answer 1

I found out the answer. The following command compiled correctly. The include statement had to be changed to...

#include<SDL2/SDL.h>
and the correct compile command is...
c++ -o helloworld helloWorld.cpp -framework SDL2

I could also have used g++. On my system both c++ and g++ are symlinks to the same gnu compiler which happens to be the latest version I have installed on the system.

the option -L is a unix linker option and does not work on a MAC. The dev's for GCC were kind enough to include MAC specific linker options in the form of -framework. These serve to follow the mac tradition of how and where they like to store libraries. You can link several frameworks together by separating them with a comma. So for example i could also do -framework SDL2,SDL2_mixer as long as my source has

#include<SDL2_mixer/SDL_mixer.h> 

When compiling this default search location for libraries is /Library/Frameworks. The include statement is cross platform compatable and the mac gnu linker knows that if I say

#include<SDL2/SDL.h> 

that that header will be found at /Library/Frameworks/SDL2.framework/Headers

The -IPATH option still works on mac and can be used to pass alternate search locations for header and source files just like it works in unix.

Answer 2

You need to put the linking flags last on the line:

g++ -I/Library/Frameworks/SDL2.framework/Headers  helloworld.cpp -L/Library/Frameworks/SDL2.framework/ -lSDL2