How can I define element size dynamically ?

[whatagoodname]

In my project, I need multiple producer threads to generate objects of a certain data type, and the size of this object is determined by an externally passed JSON during program runtime. However, it seems that our lock-free queue can only allocate memory based on the compile-time-specified T and sizeof(T)? I have tried using as T and then enqueuing n chars in bulk mode, but the speed is much slower compared to when T = std::array<char, n>. Is there any way for me to dynamically modify the element size recognized by the lock-free queue? Does this require modifying the source code to achieve?

[cameron314]

All elements need to be the same size. You can use a type that wraps a variable-length allocation, however, such as std::string.

[whatagoodname]

Of course, the same length is required. What I want to say is whether I can define the size of elements during program runtime under the premise that each element has the same length.
For example, I dynamically define a tuple object where each object is of type {int, double, long long} and has a size of 24 bytes, which is continuously allocated on the heap by a certain function. After creating a concurrent_queue, how can I make the queue recognize that the size of its objects is 24 bytes?

[cameron314]

That's not possible with C++. All types are known at compile time. You could use workarounds such as dynamically choosing between queues of different types at runtime but the type still has to be known upfront for each operation.

[whatagoodname]

I think it is possible, as long as passing in enough stuff，like constructors or something. Anyway, thanks a lot!