#include "sqlite/sqlite3.h"

class foo
{
    public:
       static sqlite3 *db;
       static void connect();
}

#include "foo.h"

sqlite3 foo::*db = nullptr;

foo::connect(){

   //sqlite3 *db;   //<-this works
   char *zErrMsg = 0;
   int rc;

   rc = sqlite3_open("test.db", &db);

   if( rc ){
      fprintf(stderr, "Can't open database: %sn", sqlite3_errmsg(db));
      exit(0);
   }else{
      fprintf(stderr, "Opened database successfullyn");
   }
   //sqlite3_close(db); // close connection when program is exiting. Not here.

}