I'm proposing a small boost library:

struct minimal_init {};

template <typename T>
struct minimal_constructible : public T
{
minimal_constructible() : T(minimal_init()) {}

};

The purpose of this is to enable vectors of simple structs (containing only POD members)

to have resize calling a do-nothing constructor. Let's say that I have a loop that I'd like to

calculate in parallel:

struct Dummy
{
Dummy(int a_=0) : a(a_) {}
Dummy(const minimal_init &) {} // Without a v-table, this shouldn't need to touch any part of the created object?

int a;
};

void foo()

{

#define N 100

std::vector<minimal_constructible<Dummy> > data;

data.resize(N);

#pragma omp parallel for

for (size_t i=0;i<N;++i)

data[i].a=i;

}

Using reserve+push_back is unlikely to create a properly sorted vector.

Ideally, we'd add a resize member to std::vector that takes a template T2 that is different

from T, just like emplace_back does, but that won't happen soon.

I'll probably want to add a few things to make minimal_constructible<T> behave more

like a T, but I really liked the idea of a five line boost library ;)

Good idea, or not?

Thanks in advance,

Henrik