Fixed-Size Large Byte Array in C++

[ElliotHYLee]

If anyone can advise, I'd appreciate it.

in C++

struct 
...
uint8_t bytes[IMAGE_SIZE];  // 1280*720*4 =  ~ 3MB
...

This carshes. Both Claud and GPT say near 3MB data cannot loan the empty space more than 1MB. Okay, the stack limit.

What I found working is

static uint8_t bytes[IMAGE_SIZE]; 

or

iox::vector<uint8_t, IMAGE_SIZE> image_data; // NOLINT

Now, static may work but in practice, all the instances will share.

So, my last option is iox:vector.

However,

auto sample = publisher.loan_uninit().expect("acquire sample");
new (&sample.payload_mut()) ComplexDataType {};  // Constructs the vectors properly
auto& payload = sample.payload_mut();

Due to my lacking c++ backgorund, i'm purely curious..

the iox::vector definition comes with the max size, why does it still need to be created like this?

[elfenpiff]

@ElliotHYLee In linux you have usually a stack size of around 8mb. If you add the C/C++ static keyword the variable is stored in the data segment and not the stack of the program. If you use the iox::vector and construct it like this:

new (&sample.payload_mut()) ComplexDataType {}; 

You perform a placement new directly inside the shared memory, which is not the stack memory, and therefore it works.

[ElliotHYLee]

#pragma comment(linker, "/STACK:8388608") would work for stand alone c++ windows with iceoryx2. But my use case is to build a DLL for .NET, and this is not guaranteed if it's called at runtime.

Anyways, this isn't an iox2 topic, so let me close the discussion here until C# binding comes out!