Re: how to separate the implementation of inline functions?

[E. Robert Tisdale]

Sean McManus wrote:

> I can get inline to work successfully
> but only when it's in the .h file along with the class declarations.
> For example:
>
> class myClass { // this works
>     inline void myFunc() { ... } //... do something inline
> };
>
> // the code below does not work in g++, but it should as far as I know
> class myClass { // in the .h
>     inline void myFunc();

Don't use the inline qualifier inside the class definition!

> };
>
> void myClass::myFunc() { // in .cpp
>     // ...do something inline
> }
>
> It gives the warning message
> warning: inline function `void myClass::myFunc()' used but never defined
>
> undefined reference to `myClass::myFunc()'
>
> It looks like this is causing a linker error.

You can do this:

        > cat myClass.h
        #ifndef GUARD_MYCLASS_H
        #define GUARD_MYCLASS_H 1

        #include <iostream>

        // The code below does not work in g++,
        // but it should as far as I know
        class myClass {
        public:
          void myFunc(void);
          };

        #endif//GUARD_MYCLASS_H

        > cat myClass.cpp
        #include "myClass.h"

        void myClass::myFunc(void) {
          std::cout << "Do something." << std::endl;
          }

        > cat main.cpp
        #include "myClass.h"

        int main(int argc, char* argv[]) {
          myClass object;
          object.myFunc();
          return 0;
          }

        > g++ -Wall -ansi -pedantic -o main main.cpp myClass.cpp
        > ./main
        Do something.

Or you can do this:

        > cat myClass.h
        #ifndef GUARD_MYCLASS_H
        #define GUARD_MYCLASS_H 1

        #include <iostream>

        // The code below does not work in g++,
        // but it should as far as I know
        class myClass {
        public:
          void myFunc(void);
          };

        inline
        void myClass::myFunc(void) {
          std::cout << "Do something." << std::endl;
          }

        #endif//GUARD_MYCLASS_H

        > cat main.cpp
        #include "myClass.h"

        int main(int argc, char* argv[]) {
          myClass object;
          object.myFunc();
          return 0;
          }

        > g++ -Wall -ansi -pedantic -o main main.cpp
        > ./main
        Do something.