Static storage duration
From cppreference.com
An object whose identifier is declared without the storage-class specifier _Thread_local, and either with external or internal linkage or with the storage-class specifier static, has static storage duration. Its lifetime is the entire execution of the program and its stored value is initialized only once, prior to program startup.
[edit] Notes
Since its stored value is initialized only once, an object with static storage duration can profile the invocations of a function.
The other use of the keyword static is file scope.
[edit] Example
Profiling the invocations of function f().
Run this code
#include <stdio.h> void f (void) { static int count = 0; /* static variable */ int i = 0; /* automatic variable */ printf("%d %d\n", i++,count++); return; } int main(void) { for (int ndx=0; ndx<10; ++ndx) f(); return 0; }
Possible output:
0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9
