C the same global variable defined in different files

Question

I am reading this code from here(in Chinese). There is one piece of code about testing global variable in C. The variable a has been defined in the file t

Answer 1

At the time foo is being compiled, the b that is in scope is the two ints vector {2, 4} or 8 bytes when an sizeof(int) is 4. When main is compiled, b has just been redeclared as an int so a size of 4 makes sense. Also there is probably "padding bytes" added to the struct after "a" such that the next slot (the int) is aligned on 4 bytes boundary.