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#include <iostream>
#include <functional>
#include <utility>
 
#define PP_CAT(a, b) PP_CAT_I(a, b)
#define PP_CAT_I(a, b) a ## b
 
template<typename F>
struct scope_exit_t {
    scope_exit_t(F & f) : f(f) {}
    ~scope_exit_t() { std::cout << "by lvalue: "; f(); }
private:
    F & f;
};
 
template<typename F>
struct scope_exit_t<F&&> {
    scope_exit_t(F && f) : f(f) {}
    ~scope_exit_t() { std::cout << "by rvalue: "; f(); }
private:
    F f;
};
 
struct scope_exit_helper {
    template<typename F>
    scope_exit_t<F&&> operator->*(F && f) const {
        return scope_exit_t<F&&>(std::forward<F>(f));
    }
};
 
#define scope_exit_base auto PP_CAT(scope_exit_, __LINE__) = scope_exit_helper() ->*
#define scope_exit scope_exit_base [&] ()
#define scope_exit_2 scope_exit_base
 
struct fun_obj {
    void operator()() { std::cout << "fugafuga\n"; }
};
 
void f() {
    std::cout << "私はカモメ\n";
}
 
void g(int x) {
    std::cout << "x\n";
}
 
int main() {
    scope_exit { std::cout << "hogehoge\n"; };
    scope_exit { std::cout << "piyopiyo\n"; };
    scope_exit_2 f;
    fun_obj x;
    scope_exit_2 x;
    scope_exit_2 std::bind(g, 10);
}
 

prog.cpp:17: error: template argument 1 is invalid
prog.cpp:26: error: template argument 1 is invalid
prog.cpp:26: error: expected ‘,’ or ‘...’ before ‘&&’ token
prog.cpp: In member function ‘int scope_exit_helper::operator->*(F) const’:
prog.cpp:27: error: template argument 1 is invalid
prog.cpp:27: error: ‘forward’ is not a member of ‘std’
prog.cpp:27: error: ‘f’ was not declared in this scope
prog.cpp:27: error: ‘forward’ is not a member of ‘std’
prog.cpp:27: error: expected primary-expression before ‘>’ token
prog.cpp: In function ‘int main()’:
prog.cpp:48: error: ISO C++ forbids declaration of ‘scope_exit_48’ with no type
prog.cpp:48: error: expected primary-expression before ‘[’ token
prog.cpp:48: error: expected primary-expression before ‘]’ token
prog.cpp:48: error: expected ‘,’ or ‘;’ before ‘{’ token
prog.cpp:49: error: ISO C++ forbids declaration of ‘scope_exit_49’ with no type
prog.cpp:49: error: expected primary-expression before ‘[’ token
prog.cpp:49: error: expected primary-expression before ‘]’ token
prog.cpp:49: error: expected ‘,’ or ‘;’ before ‘{’ token
prog.cpp:50: error: ISO C++ forbids declaration of ‘scope_exit_50’ with no type
prog.cpp:52: error: ISO C++ forbids declaration of ‘scope_exit_52’ with no type
prog.cpp:53: error: ISO C++ forbids declaration of ‘scope_exit_53’ with no type
prog.cpp:53: error: ‘bind’ is not a member of ‘std’
prog.cpp:48: warning: unused variable ‘scope_exit_48’
prog.cpp:49: warning: unused variable ‘scope_exit_49’
prog.cpp:50: warning: unused variable ‘scope_exit_50’
prog.cpp:52: warning: unused variable ‘scope_exit_52’
prog.cpp:53: warning: unused variable ‘scope_exit_53’

Standard output is empty