namespaces from header files in c++ -

i have created noname namespace variables inside in header, want initialize them in .cpp , see in main.cpp. noname namespace expecting work fine without mentioning namespace in .cpp. error if in .cpp had totally new , b. has idea how resolve it?

xx.h

namespace {     int a;     int b; } 

.cpp

#include "xx.h" = 5; b = 10; 

main.cpp

#include <iostream> #include "xx.h" int main() {        std::cout << "values" << << b << std::endl; } 

you may not use assignment statements outside functions. may declare or/and define objects . valid code be

namespace {     int = 5;     int b = 10; } 

main.cpp

#include <iostream> #include "xx.h" int main() {        std::cout << "values" << << b << std::endl; } 

take account objects declared in unnamed namespaces have internal linkage. means if header included in more 1 module in each module declares separate namespace.

consder following example

unnamed.h

namespace {     int = 5;     int b = 10; }  void f(); 

second.cpp

#include <iostream> #include "unnamed.h"  void f() {     = 10; b = 5;     std::cout << "a = " << << ", b = " << b << std::endl; } 

main.cpp #include #include "unnamed.h"

int main() {     f();     std::cout << "a = " << << ", b = " << b << std::endl;      return 0; } 

the output is

a = 10, b = 5 = 5, b = 10