Static

A static variable has 3 primary uses:

• A static variable in a function will retain its value between function calls.

  • Consider the following code snippet:

    //Setup code
    
    void spike_crash_counter_output()
    {
      static uint8_t number_of_crashes = 0;
      number_of_crashes++;
      printf("Number of crashes: %d\n", number_of_crashes);
    }
    
    int main()
    {
      spike_crash_counter_output();
      spike_crash_counter_output();
    }
    
    /*Output:
    Number of crashes: 0
    Number of crashes: 1 */

• A variable declared as static in a file is a localized global, i.e. the variable cannot be seen by other files, only in the file that it was declared in.

• A function declared as static in a file may only be called by functions in the same file, i.e. the function cannot be seen by other files, only in the file that it was declared in.