static

static variables exist in the data portion of a program. They are only initialized once, and they can persist throughout the execution of the program. They are also strictly internal, and they only exist in the scope they were defined in. For example:

#include <stdio.h>

void add_numbers()
{
    static a = 10;
    int b = 10;
    
    a += 5;
    b += 5;
    
    printf("a: %d, b: %d", a, b); 
}

int main(void)
{
    add_numbers();
    add_numbers();
    add_numbers();
    
    return 0;
}

The output will be:

a: 15, b: 15
a: 20, b: 15
a: 25, b: 15

So they are useful for fixes circumventing the fact that you can’t return pointers. But they aren’t thread-safe (safe from other threads of execution, if your program is multithreaded), so just use malloc()

#C #C/features