I'm not sure how this depends on the language, per se. Basically you want very special behaviour here: Allocate a piece of memory, preferrably so that it doesn'

I'm not sure how this depends on the language, per se. Basically you want very special behaviour here: Allocate a piece of memory, preferrably so that it doesn't end up accidentally in permanent storage and later clear it and deallocate it again. C gives you no such facilities to do so, but so do very few other languages (if any). The correct course here would rather be to ask the OS to do that for you. You can tell the memory allocator to never page out the block you get. Every OS has a syscall to zero memory that isn't subject to compiler optimisations. Honestly, in my eyes, this is a place where the language is specified in a way that it cannot ever guarantee what you're trying to achieve and in that case you're best off not relying on the language, but on other things that can make such guarantees.