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authorFred Drake <fdrake@acm.org>2002-04-23 21:21:20 (GMT)
committerFred Drake <fdrake@acm.org>2002-04-23 21:21:20 (GMT)
commit99d17006c12d2e768a7b8e1c706adf6b4e152140 (patch)
tree6f964ca7bf9efe1786c58abfd354f75dfacdc3be /Doc
parent95df3fd15933dafbb2f1140d011794cc8ccbdc76 (diff)
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Add text about circular references caused by storing frames in local
variables. This closes SF bug #543148.
Diffstat (limited to 'Doc')
-rw-r--r--Doc/lib/libinspect.tex16
1 files changed, 16 insertions, 0 deletions
diff --git a/Doc/lib/libinspect.tex b/Doc/lib/libinspect.tex
index 186fd58..a1293f0 100644
--- a/Doc/lib/libinspect.tex
+++ b/Doc/lib/libinspect.tex
@@ -321,3 +321,19 @@ which occurs.}
Return a list of frame records for the stack below the current
exception.
\end{funcdesc}
+
+Stackframes stored directly or indirectly in local variables can
+easily cause reference cycles. Though the cycle detector will catch
+these, destruction of the frames (and local variables) can be made
+deterministic by removing the cycle in a \keyword{finally} clause.
+This is also important if the cycle detector was disabled when Python
+was compiled or using \function{gc.disable()}. For example:
+
+\begin{verbatim}
+def handle_stackframe_without_leak():
+ frame = inspect.currentframe()
+ try:
+ # do something with the frame
+ finally:
+ del frame
+\end{verbatim}