i know that if we declare a variable in one source file then we have to declare that same variable with extern prefix in some other source file which are to be linked later while compiling. soppose we have 3 source files and among those 3 files 2 have declared a variable without extern prefix and one is declared with extern prefix. so which decleration is considered by the source file which has declared that variable with extern prefix.
ex:
file1.c-----
//global variables
int a = 6;
file2.c------
//global variables
int a = 3;
file3.c
//global variables
extern int a;
so in file3.c which definition is considered????