automatic-function-scope-variables.md

description	Learn more about: Automatic (function scope) variables
title	Automatic (function scope) variables
ms.date	04/22/2019
helpviewer_keywords	automatic variables variables, automatic functions [C++], scope scope, declared within functions
ms.assetid	6e1a14c2-1fb0-4937-8628-8d963cc35ed4

Automatic (function scope) variables

A variable declared within a function can only be used within the scope of that function.

// LNK2019_AV.cpp
// compile with: /c
void test(void);

static int lnktest3 = 3;
int lnktest4 = 4;

int main() {
   static int lnktest1 = 1;
   int lnktest2 = 2;
   test();
}

and then,

// LNK2019_AV_2.cpp
// compile with: LNK2019_AV.cpp
// LNK2019 expected
extern int lnktest1;
extern int lnktest2;
extern int lnktest3;
extern int lnktest4;

void test(void) {
   int i = 0;
   i = lnktest1;
   i = lnktest2;
   i = lnktest3;
   i = lnktest4;   // OK
}

See also

Linker tools error LNK2019