Foundations Updated 2026-09 View as Markdown

Static

static is a keyword in the C programming language. It can be used with variables and functions. By default, variables are local to the scope in which they are defined.

static is a keyword in the C programming language. It can be used with variables and functions.

What is a static variable?#

By default, variables are local to the scope in which they are defined. Variables can be declared as static to increase their scope up to file containing them. As a result, these variables can be accessed anywhere inside a file.

Consider the following scenario – we want to count the runners participating in a race:

#include<stdio.h>
int runner() {
    int count = 0;
    count++;
    return count;
}

int main()
{
    printf("%d ", runner());
    printf("%d ", runner());
    return 0;
}

We will see that count is not updated because it is removed from memory as soon as the function completes. If static is used, however:

#include<stdio.h>
int runner()
{
    static int count = 0;
    count++;
    return count;
}

int main()
{
    printf("%d ", runner());
    printf("%d ", runner());
    return 0;
}

What is a static function?#

By default, functions are global in C. If we declare a function with static, the scope of that function is reduced to the file containing it.

The syntax looks like this:

static void fun(void) {
   printf("I am a static function.");
}

Static vs Global?#

While static variables have scope over the file containing them making them accessible only inside a given file, global variables can be accessed outside the file too.

55 100 150

#include <stdio.h>
int sum (int num) {
    static int total = 0;
    total += num;
    return total;
}

int main() {
    printf("%d ",sum(55));
    printf("%d ",sum(45));
    printf("%d ",sum(50));
    return 0;
}