How do I share a global variable between c files

Question

If i define  a global variable in a  c file  how can i use the value of the same variable in another  c file   file1 c   include lt stdio h gt   int i 10   int main     printf   d  i   return 0      file2 c   include lt stdio h gt   int main       some data regarding i printf   d  i   return 0      How can the second file use the value of i from the first file here

User · Answer

In the second  c file use extern keyword with the same variable name

User · Answer

Do same as you did in file1 c In file2 c    include  lt stdio h gt    extern int i     This declare that i is an int variable which is defined in some other file    int main void       your code     If you use int i  in file2 c under main   then i will be treated as local auto variable not the same as defined in file1 c

User · Answer

If you want to use global variable i of file1 c in file2 c  then below are the points to remember    main function shouldn t be there in file2 c now global variable i can be shared with file2 c by two ways  a  by declaring with extern keyword in file2 c  i e extern int i  b  by defining the variable i in a header file and including that header file in file2 c

User · Answer

using extern  lt variable type gt   lt variable name gt  in a header or another C file

User · Answer

file 1   int x   50    file 2   extern int x   printf   d   x

User · Answer

Use the extern keyword to declare the variable in the other  c file  E g    extern int counter    means that the actual storage is located in another file  It can be used for both variables and function prototypes

User · Answer

Use extern keyword in another  c file

[c] How do I share a global variable between c files?

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