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-rw-r--r--Doc/library/sys.rst20
1 files changed, 17 insertions, 3 deletions
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index e0668b8..b4666d9 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -173,7 +173,11 @@ always available.
Call ``func(*args)``, while tracing is enabled. The tracing state is saved,
and restored afterwards. This is intended to be called from a debugger from
- a checkpoint, to recursively debug some other code.
+ a checkpoint, to recursively debug or profile some other code.
+
+ Tracing is suspended while calling a tracing function set by
+ :func:`settrace` or :func:`setprofile` to avoid infinite recursion.
+ :func:`!call_tracing` enables explicit recursion of the tracing function.
.. data:: copyright
@@ -1471,13 +1475,16 @@ always available.
its return value is not used, so it can simply return ``None``. Error in the profile
function will cause itself unset.
+ .. note::
+ The same tracing mechanism is used for :func:`!setprofile` as :func:`settrace`.
+ To trace calls with :func:`!setprofile` inside a tracing function
+ (e.g. in a debugger breakpoint), see :func:`call_tracing`.
+
Profile functions should have three arguments: *frame*, *event*, and
*arg*. *frame* is the current stack frame. *event* is a string: ``'call'``,
``'return'``, ``'c_call'``, ``'c_return'``, or ``'c_exception'``. *arg* depends
on the event type.
- .. audit-event:: sys.setprofile "" sys.setprofile
-
The events have the following meaning:
``'call'``
@@ -1499,6 +1506,9 @@ always available.
``'c_exception'``
A C function has raised an exception. *arg* is the C function object.
+ .. audit-event:: sys.setprofile "" sys.setprofile
+
+
.. function:: setrecursionlimit(limit)
Set the maximum depth of the Python interpreter stack to *limit*. This limit
@@ -1558,6 +1568,10 @@ always available.
If there is any error occurred in the trace function, it will be unset, just
like ``settrace(None)`` is called.
+ .. note::
+ Tracing is disabled while calling the trace function (e.g. a function set by
+ :func:`!settrace`). For recursive tracing see :func:`call_tracing`.
+
The events have the following meaning:
``'call'``