Max vector size

[sargon94]

Is there a maximum size a vector can reach? I know it's over 5 million chars (since I've already done that) but can it hold 25 million data points?

[Cubbi]

It's limited by the largest contiguous chunk of RAM your OS can allocate for you or the return value of vector<>::max_size(), whichever is smaller.

For example, on this dev box I have 256 GB RAM, but max_size is only 2G,

1 2 3 4 5

for(std::vector<char>::size_type sz = 1; ; sz *= 2) { std::cerr << "attempting sz = " << sz << '\n'; std::vector<char> v(sz); }

attempting sz = 536870912 attempting sz = 1073741824 attempting sz = 2147483648 aCC runtime: Uncaught exception of type "std::length_error". aCC runtime: what(): vector<...>::vector(n,v): vector too long

[sargon94]

Thanks! That's what I hoped.

cheers!

[ascii]

I have 256 GB RAM

Whyyyyyyyyyyyyy would you ever need that much???

[Moschops]

Image and video processing springs to mind as one example. Decompress a blu-ray and see how much RAM you'd like then :p

[sargon94]

When I asked mine, it also said 2GB. *Might* be an issue actually, is there any way to up that limit?

Decompress a blu-ray and see how much RAM you'd like then

And that kids, is a little thing we like to call pirating, or maybe something else but usually pirating.

[Cubbi]

Whyyyyyyyyyyyyy would you ever need that much???

it's not a personal computer.

Just re-ran it on a personal linux box: max_size is 18446744073709551615 (which happens to be std::numeric_limits<std::size_t>::max())

[...]
attempting sz = 4294967296
attempting sz = 8589934592
attempting sz = 17179869184 (my box starts swapping)
attempting sz = 34359738368 (that's too much, I only have 24 GB ram)
terminate called after throwing an instance of 'std::bad_alloc'

When I asked mine, it also said 2GB. *Might* be an issue actually, is there any way to up that limit?

max_size is typically literally the maximum integer value that can be used as the index, which means it cannot be surpassed without writing your own container or switching the development environment to one where size_t is 64 bit

[Moschops]

And that kids, is a little thing we like to call pirating, or maybe something else but usually pirating.

I was thinking more professional animation studio like Pixar and what have you, but sure, pirates too.

[kbw]

Is there a maximum size a vector can reach?

Yes, vector::max_size()
http://en.cppreference.com/w/cpp/container/vector/max_size

[sargon94]

I was thinking more professional animation studio like Pixar and what have you

You decompress Blu-ray for this? To quote ascii:

Whyyyyyyyyyyyyy???

@Cubbi: s***, guess I'll be doing that then.

[Moschops]

You decompress Blu-ray for this?

No, we have the original that needs to be compressed.

[sargon94]

Ahh, I see clarity now, gotcha. Pretty nice stuff, it'd make a heck of a hobby/job/both.