how to declare and define global variables in order to access them from all headers/source files properly

by

In header file only do 

namespace gi {
    extern MapInformation mapInf;
};

In CPP file provide the actual definition. 

namespace gi {
    MapInformation mapInf;
};

It will work as you intend.

If you are using the MapInformation across dynamic link library boundaries you might have to link against the library that includes the definition cpp file. Also on Window you might have to use dllimport/dllexport

More Related Contents:

  1. Are global variables bad? [closed]
  2. What happens to global and static variables in a shared library when it is dynamically linked?
  3. Why are global and static variables initialized to their default values?
  4. Does C++ call destructors for global and class static variables?
  5. When are static and global variables initialized?
  6. Is std::cout guaranteed to be initialized?
  7. static and extern global variables in C and C++
  8. C++ singleton vs. global static object
  9. Trouble launching CUDA kernels from static initialization code
  10. Defining Global Variables Between Two .cpp Files [duplicate]
  11. C++ Global variable declaration
  12. Does C have One Definition Rule like C++?
  13. Are global variables in C++ stored on the stack, heap or neither of them?
  14. How to execute a piece of code only once?
  15. What is default storage class for global variables?
  16. What are the pros and cons in use of global variables? [closed]
  17. What is Div if not division [duplicate]
  18. How can I profile C++ code running on Linux?
  19. Why are C character literals ints instead of chars?
  20. How do I print out the contents of a vector?
  21. Can I access private members from outside the class without using friends?
  22. system(“pause”); – Why is it wrong?
  23. Do rvalue references to const have any use?
  24. Why not infer template parameter from constructor?
  25. How to build and use Google TensorFlow C++ api
  26. Why does ostream_iterator not work as expected?
  27. How to programmatically cause a core dump in C/C++
  28. How do I return a char array from a function?
  29. What C++ library should I use to implement a HTTP client? [closed]
  30. Why is this C++ wrapper class not being inlined away?

Leave a Comment