gc.md 1.7 KB
icon: package
label: gc
gc
Control the current VM's tracing garbage collector.
| Function | Behavior |
|---|---|
isenabled() |
Whether automatic collection is enabled. |
enable(), disable() |
Enable/disable automatic collection. |
collect() |
Run a full collection now and return the number of reclaimed objects. |
collect_hint() |
Collect if the allocation threshold calls for it; return the reclaimed count. |
setup_debug_callback(callback) |
Register collection diagnostics; pass None to remove the callback. |
is_tracked(obj), track(obj), untrack(obj) |
Inspect or change whether the collector traverses an object's references. |
import gc
cycle = []
cycle.append(cycle)
del cycle
reclaimed = gc.collect()
assert type(reclaimed) is int
assert reclaimed >= 1
Disabling automatic collection does not stop allocation or prevent explicit
collect()/collect_hint() calls. A frame-driven application can disable
automatic collection, call collect_hint() at an appropriate frame boundary,
and re-enable it when leaving that mode. Memory may grow between collections;
measure the effect before adopting this policy.
untrack() is an advanced optimization for containers whose contents do not
need tracing, such as a list containing only integer values. If an untracked
container later contains GC-managed objects, its children can be reclaimed
while still in use. Track it again before storing such values.
Native code must also keep references visible to the collector; see C API lifetimes. Full declarations: gc.pyi.