CODEWITHSUNDEEP
c++c++17
darune
darune

Reputation: 11000

What's the most suitable c++ replacement of calloc?

The title says it.

I have tried:

new char[nSize];

but it can return uninitialized memory. where as calloc ensures a zero-initialization.

I could call memset, etc. - but isn't there a more direct way ?

Upvotes: 2

Views: 451

Answers (1)

eerorika
eerorika

Reputation: 238401

What's the most suitable c++ replacement of calloc?

For most purposes, std::vector. Or std::string if you intend to represent a character string. It will automatically delete whatever memory it allocates.

For data structures that contain many arrays that are not mutually contiguous, you might want to avoid the slightly-larger-than-pointer size of std::vector, and instead might opt for unique pointer:

auto ptr = std::make_unique<char[]>(nSize);

You can use value initialisation with a new expression as well. This is what std::make_unique does internally:

new char[nSize]();

But I would not recommend allocations without a RAII container.

As mentioned by geza, calloc may be optimised (on some systems) such that it may elide setting the memory to zero when allocating a large block. If such optimisation applies to your case, and is measurably significant, then there may be an argument for using std::calloc in C++.

Upvotes: 4

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