Header file and extern keyword

Question

I am having a lot of issue using extern variable and header files. I have read through sections of books and searched the web for hours but I haven\'t been able to figure out. A

Answer 1

gI must be declared above main:

int gI = 0;

int main(void)
{
    ...
}

By doing this gI has file scope and external linkage.

Perhaps a better place to declare gI would be in sample.c, if there is such a file.