memory.size: Report on Memory Allocation (on Windows)
On MS Windows,
memory.size() reports the current or maximum memory allocation of
the malloc function used in this version of R.
memory.limit() reports or increases the limit in force
on the total allocation.
On non-Windows platforms
stubs which report infinity (Inf) with a warning.
memory.size(max = FALSE)
memory.limit(size = NA)
logical. If TRUE the maximum amount of memory
obtained from the OS is reported, if FALSE the amount
currently in use, if NA the memory limit.
numeric. If NA report the memory limit, otherwise
request a new limit, in Mb. Only values of up to 4095 are allowed on
32-bit R builds, but see ‘Details’.
A number: On Windows, size in Mb (1048576 bytes), rounded to 0.01 Mb for memory.size
and rounded down for memory.limit.
On other platforms: Inf always.
Command-line flag --max-mem-size sets the maximum value of
obtainable memory (including a very small amount of housekeeping
overhead). This cannot exceed 3Gb on 32-bit Windows, and most
versions are limited to 2Gb. The minimum is currently 32Mb.
If 32-bit R is run on most 64-bit versions of Windows the maximum
value of obtainable memory is just under 4Gb. For a 64-bit versions
of R under 64-bit Windows the limit is currently 8Tb.
Memory limits can only be increased.
Environment variable R_MAX_MEM_SIZE provides another way to
specify the initial limit.