does rust use the space of invalid variables on the stack until the end of scope?

Question

we know that when the ownership of a variable moved, the variable is not valid anymore until the end of the scope when its' space become free in stack. but what happened to the memory space that becomes invalid? does it waste until the end of scope?

I don't have any idea of how OS managing the stack

score 0 · Answer 1 · answered Mar 19 '23 at 14:53

0

The OS does not manage the stack (besides allocating and possibly growing it), the program does.

Putting that aside, yes, the space is wasted, but usually this is not a problem. Also, the compiler can sometimes optimize that and re-use the same space for other variables, if their lifetime do not overlap.

answered Mar 19 '23 at 14:53

Chayim Friedman

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is there anyway that I can use that space by myself in rust? – Mohamad Mahdi Reisi Mar 19 '23 at 17:39
and do you have any reference for that? – Mohamad Mahdi Reisi Mar 19 '23 at 17:39
@MohamadMahdiReisi You cannot reuse this space (except using inline assembly). – Chayim Friedman Mar 19 '23 at 17:41
https://stackoverflow.com/questions/67499399/why-does-the-rust-compiler-not-reuse-the-memory-on-the-stack-after-an-object-is – Mohamad Mahdi Reisi Mar 19 '23 at 17:56
that seems it doesn't reuse the memory – Mohamad Mahdi Reisi Mar 19 '23 at 17:57

does rust use the space of invalid variables on the stack until the end of scope?

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