What supported behaviour, if any, may applications rely on for inherited RLIMIT_AS when launching a process on macOS on Apple silicon using posix_spawn and subsequent exec transitions?
An older published XNU header defines RLIMIT_AS:
XNU resource.h (immutable revision)
I am looking for the documented support and virtual-address-space accounting scope, including exclusions.
For a finite limit already set in the launching process, does any documented guarantee cover the new process from its first executable or dynamic-loader mapping and across later exec transitions, or does the limit take effect at a later stage? If the limit cannot be applied, does launch abort before any target user code executes, what failure is reported, and can mappings occur before that failure? An explicit statement that this guarantee is not provided would also be helpful.
My question concerns virtual address space, rather than resident memory or a language runtime's heap. A successful setter or getrlimit readback by itself does not answer when the limit takes effect.
If an answer relies on published XNU code, what public release/build record would be needed to relate an immutable source revision to a released macOS build on Apple silicon, and what limits apply to that correspondence? I am asking about the supported public interface and publicly available documentation/source, without requesting private implementation details.
A link to an existing answer or the documented boundary would be appreciated.
