Converting C to C++: typdef generating error

Question

I need to convert a .c file into .cpp file and I came across this declaration:

 typedef void handler_t(int);

 handler_t *Signal(int signum, handler_t *handler);

I included those two lines of code in the header file, and I add the actual function declaration function in the .cpp file.

 handler_t *Signal(int signum, handler_t *handler){ ...... } 

When I do this I get the error: "handler_t does not name a type".I have never worked before with typdef in C or C++, so can someone explain to me why I am getting an error?

---

My classes as requested:

 #ifndef A_H
 #define A_H

 class A
 {
     public:
       A();
       virtual ~A();

       typedef void handler_t(int);
       handler_t* Signal(int signum, handler_t *handler);

     protected:
     private:
 };

   #endif // A_H

/////////////

   #include "A.h"

   A::A()
   {
   }

   A::~A()
   {
   }

   handler_t* A::Signal(int signum, handler_t *handler) {

     ...........

    }

error:

    |694|error: ‘handler_t’ does not name a type|

Answer 1

Try changing it to:

typedef void (*handler_t)(int);

and:

handler_t Signal(int signum, handler_t handler);

For reference check out signal() which does it like this:

#include <signal.h>

typedef void (*sighandler_t)(int);

sighandler_t signal(int signum, sighandler_t handler);

Actually, looking at your new code, I think you have to do this:

A::handler_t* A::Signal(int signum, A::handler_t *handler)

I think your new error "undefined reference to main" is unrelated to the question asked. See this post for some ideas.