py/gc: Add gc_sweep_all() function to run all remaining finalisers.

This patch adds the gc_sweep_all() function which does a garbage collection
without tracing any root pointers, so frees all the memory, and most
importantly runs any remaining finalisers.

This helps primarily for soft reset: it will close any open files, any open
sockets, and help to get the system back to a clean state upon soft reset.

1 files changed, 3 insertions, 0 deletions

diff --git a/py/gc.h b/py/gc.h
index 739349c1f..73d86e6c3 100644
--- a/py/gc.h
+++ b/py/gc.h
@@ -45,6 +45,9 @@ void gc_collect_start(void);
 void gc_collect_root(void **ptrs, size_t len);
 void gc_collect_end(void);
 
+// Use this function to sweep the whole heap and run all finalisers
+void gc_sweep_all(void);
+
 void *gc_alloc(size_t n_bytes, bool has_finaliser);
 void gc_free(void *ptr); // does not call finaliser
 size_t gc_nbytes(const void *ptr);