Report information on the C stack size and usage (if available).
Cstack_info()An integer vector. This has named elements
The size of the stack (in bytes), or NA if unknown.
The estimated current usage (in bytes), possibly NA.
1 (stack grows down, the usual case) or
-1 (stack grows up).
The current evaluation depth (including two calls
for the call to Cstack_info).
On most platforms, C stack information is recorded when R is
initialized and used for stack-checking. If this information is
unavailable, the size will be returned as NA, and
stack-checking is not performed.
The information on the stack base address is thought to be accurate on
Windows, Linux (using glibc), macOS and FreeBSD but a heuristic
is used on other platforms. Because this might be slightly
inaccurate, the current usage could be estimated as negative. (The
heuristic is not used on embedded uses of R on platforms where the
stack base information is not thought to be accurate.)
The ‘evaluation depth’ is the number of nested R expressions
currently under evaluation: this has a limit controlled by
options("expressions").