duplicate symbol MyFunction in xcode
If you get the following error when trying to compile a C (or Objective C) program in XCode:
duplicate symbol MyFunction
(null): 1 duplicate symbol for architecture x86_64
then the problem is that you’ve included a .c file using #include directive or #import directive instead of including the .h file.
If you’ve created some functions in a separate .c file (or .m file) don’t just import that file in your main file but create a header file too and move header definitions to that file.