Redefinition; different basic types (typedef struct)

c, extern, struct, typedef

Solution

The problem is you have `Foo.h` in `Bar.h`. And both `Foo.h` and `Bar.h` are being included in `main.cpp`, which results getting the `my_struct` definition twice in the translation unit. Have a `ifdef` directive around struct definition file. Try this -

#ifndef FOO_H
#define FOO_H

  typedef struct
  {
      int number;
  } my_struct;    

#endif

Problem

I'm having a bit of trouble trying to get structs to work properly when they are defined in different files. From as far as I can tell, the error is telling me that the struct is being defined two different times. I believe that perhaps I may need to use extern somewhere? I've tried experimenting and looking for help on Google, but to no avail. Any help at all would be most appreciated, thank you. All four of my files are below. FILE: Foo.h ``` typedef struct { int number; } my_struct; // Redefinition; different basic types ``` FILE: Foo.c ``` #include "Foo.h" #include "Bar.h" #include <stdio.h> my_struct test; int main(void) { test.number = 0; DoSomething(&test); printf("Number is: ", &test.number); } ``` FILE: Bar.h ``` #include "Foo.h" void DoSomething(my_struct *number); ``` FILE: Bar.c ``` #include "Bar.h" void DoSomething(my_struct *number) { number->number = 10; } ```

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