C++ Storage class specifiers static
Example
The static storage class specifier has three different meanings.
-
Gives internal linkage to a variable or function declared at namespace scope.
// internal function; can't be linked to static double semiperimeter(double a, double b, double c) { return (a + b + c)/2.0; } // exported to client double area(double a, double b, double c) { const double s = semiperimeter(a, b, c); return sqrt(s*(s-a)*(s-b)*(s-c)); } -
Declares a variable to have static storage duration (unless it is
thread_local). Namespace-scope variables are implicitly static. A static local variable is initialized only once, the first time control passes through its definition, and is not destroyed every time its scope is exited.void f() { static int count = 0; std::cout << "f has been called " << ++count << " times so far\n"; } -
When applied to the declaration of a class member, declares that member to be a static member.
struct S { static S* create() { return new S; } }; int main() { S* s = S::create(); }
Note that in the case of a static data member of a class, both 2 and 3 apply simultaneously: the static keyword both makes the member into a static data member and makes it into a variable with static storage duration.
