diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 36 |
1 files changed, 35 insertions, 1 deletions
@@ -51335,8 +51335,42 @@ If any finalizers are called, it returns otherwise .codn nil . -Note: the behavior is unspecified if a finalizer function calls +It is permissible for a finalizer function itself to call .codn call-finalizers . +Such a call can happen in two possible contexts: during actual +reclamation driven by garbage collection, or under the scope of a +.code call-finalizers +invocation from application code. + +Under the scope of garbage-collection-driven reclamation, the +order of finalizer calls may not be what the application logic +expects. For instance even though a finalizer registered for some object +.code A +itself invokes +.codn "(call-finalizers B)" , +it may be the case during GC reclamation that both +.code A +and +.code B +are identified as unreachable objects at the same time, and some or all +finalizers registered against +.code B +have already been called before the given +.code A +finalizer performs the explicit +.code call-finalizers +invocation against +.codn B . +Thus the the call either has no effect at all, or only calls some remaining +.code B +finalizers that have not yet been processed, rather than all of them, +as the application expects. + +The application must avoid creating a dependency on the order of +finalization calls, to prevent the situation that the finalization actions are +only correct under an explicit +.code call-finalizers +but incorrect under spontaneous reclamation driven by garbage collection. .SS* Modularization .coNP Variable @ self-path |