gc {base} | R Documentation |
A call of gc
causes a garbage collection to take place.
gcinfo
sets a flag so that
automatic collection is either silent (verbose=FALSE
) or
prints memory usage statistics (verbose=TRUE
).
gc(verbose = getOption("verbose"), reset=FALSE) gcinfo(verbose)
verbose |
logical; if TRUE , the garbage collection prints
statistics about cons cells and the vector heap. |
reset |
logical; if TRUE the values for maximum space used
are reset to the current values |
A call of gc
causes a garbage collection to take place.
This takes place automatically without user intervention, and the
primary purpose of calling gc
is for the report on memory usage.
However, it can be useful to call gc
after a large object
has been removed, as this may prompt R to return memory to the
operating system.
gc
returns a matrix with rows "Ncells"
(cons
cells), usually 28 bytes each on 32-bit systems and 56 bytes on
64-bit systems, and "Vcells"
(vector cells, 8 bytes
each), and columns "used"
and "gc trigger"
,
each also interpreted in megabytes (rounded up to the next 0.1Mb).
If maxima have been set for either "Ncells"
or "Vcells"
,
a fifth column is printed giving the current limits in Mb (with
NA
denoting no limit).
The final two columns show the maximum space used since the last call
to gc(reset=TRUE)
(or since R started).
gcinfo
returns the previous value of the flag.
Memory
on R's memory management,
and gctorture
if you are an R hacker.
reg.finalizer
for actions to happen upon garbage
collection.
gc() #- do it now gcinfo(TRUE) #-- in the future, show when R does it x <- integer(100000); for(i in 1:18) x <- c(x,i) gcinfo(verbose = FALSE)#-- don't show it anymore gc(TRUE) gc(reset=TRUE)