Simple "scope exit" macro for C++03, which supports arbitrary actions on scope exit.

scope_exit.cpp

#include <iostream>

using namespace std;

#define JOIN(a, b) JOIN_(a, b)
#define JOIN_(a, b) a ## b

#define ARG_COUNT(...) ARG_COUNT_IMP(__VA_ARGS__, 9, 8, 7, 6, 5, 4, 3, 2, 1)
#define ARG_COUNT_IMP(                        _1,_2,_3,_4,_5,_6,_7,_8,_9, N, ...) N

#define MACRO_DISPATCH(macro, ...) MACRO_DISPATCH_(macro, ARG_COUNT(__VA_ARGS__))
#define MACRO_DISPATCH_(macro, argc) MACRO_DISPATCH__(macro, argc)
#define MACRO_DISPATCH__(macro, argc) macro ## argc

#define SCOPE_EXIT(...) MACRO_DISPATCH(SCOPE_EXIT, __VA_ARGS__) (__VA_ARGS__)

#define SCOPE_EXIT3(type1, arg1,                    \
                    code)                           \
    class JOIN(scope_exit, __LINE__)                \
    {                                               \
    public:                                         \
        JOIN(scope_exit, __LINE__)                  \
                  (type1 & arg1_par)                \
            : arg1(arg1_par)                        \
        {}                                          \
                                                    \
        ~ JOIN(scope_exit, __LINE__) ()             \
        {                                           \
            code                                    \
        }                                           \
                                                    \
    private:                                        \
        type1 & arg1;                               \
    };                                              \
                                                    \
    JOIN(scope_exit, __LINE__)                      \
        JOIN(guard, __LINE__) (arg1)                \

#define SCOPE_EXIT5(type1, arg1,                    \
                    type2, arg2,                    \
                    code)                           \
    class JOIN(scope_exit, __LINE__)                \
    {                                               \
    public:                                         \
        JOIN(scope_exit, __LINE__)                  \
                  (type1 & arg1_par,                \
                   type2 & arg2_par)                \
            : arg1(arg1_par)                        \
            , arg2(arg2_par)                        \
        {}                                          \
                                                    \
        ~ JOIN(scope_exit, __LINE__) ()             \
        {                                           \
            code                                    \
        }                                           \
                                                    \
    private:                                        \
        type1 & arg1;                               \
        type2 & arg2;                               \
    };                                              \
                                                    \
    JOIN(scope_exit, __LINE__)                      \
        JOIN(guard, __LINE__) (arg1,                \
                               arg2)                \

#define SCOPE_EXIT7(type1, arg1,                    \
                    type2, arg2,                    \
                    type3, arg3,                    \
                    code)                           \
    class JOIN(scope_exit, __LINE__)                \
    {                                               \
    public:                                         \
        JOIN(scope_exit, __LINE__)                  \
                  (type1 & arg1_par,                \
                   type2 & arg2_par,                \
                   type3 & arg3_par)                \
            : arg1(arg1_par)                        \
            , arg2(arg2_par)                        \
            , arg3(arg3_par)                        \
        {}                                          \
                                                    \
        ~ JOIN(scope_exit, __LINE__) ()             \
        {                                           \
            code                                    \
        }                                           \
                                                    \
    private:                                        \
        type1 & arg1;                               \
        type2 & arg2;                               \
        type3 & arg3;                               \
    };                                              \
                                                    \
    JOIN(scope_exit, __LINE__)                      \
        JOIN(guard, __LINE__) (arg1,                \
                               arg2,                \
                               arg3)                \

int main()
{
    int a = 10;
    SCOPE_EXIT(int, a,
               { cout << a << endl; });

    bool dismissed = false;
    SCOPE_EXIT(int, a,
               bool, dismissed,
               { if (!dismissed)
                       cout << a << endl;
               });

    int a1 = 1;
    int a2 = 2;
    SCOPE_EXIT(int, a1,
               int, a2,
               bool, dismissed,
               {
                   if (!dismissed)
                       cout << a1 << " : " << a2 << endl;
               });

    dismissed = true;
}