T *t; //T is an implementation detail
t = new T; //want to avoid naming T to allow for flexibility
t = new decltype(*t); //error: cannot use 'new' to allocate a reference
t = new std::remove_reference<decltype(*t)>::type(); //clunky
This answers why decltype(*t)
returns T &
and not T
.
I can put my last line into a macro, but that seems suboptimal. Is there a better solution than what I have so far? Does this belong on Code Review?
If they're on the same line, you can use auto
to only name T
once:
auto t = new T;
Otherwise, you could create a small function template:
template <class T>
void do_new(T * &p) {
p = new T;
}
// Usage:
int main()
{
T *t;
do_new(t);
}
As @MadScienceDreams pointed out, you can extend this to allow non-default constructors:
template <class T, class... Arg>
void do_new(T * &p, Arg &&... arg) {
p = new T(std::forward<Arg>(arg)...);
}
// Usage:
int main()
{
T *t;
do_new(t);
std::string *s;
do_new(s, "Abc");
}