[3.8] bpo-39427: Document -X opt options in the CLI --help and the man page (GH-18131) (GH-18133)
https://bugs.python.org/issue39427
Automerge-Triggered-By: @pablogsal
(cherry picked from commit 41f0ef6abbd304409c55612a08788cdd59fbc8a3)
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
diff --git a/Python/initconfig.c b/Python/initconfig.c
index a30fdd1..a0b2691 100644
--- a/Python/initconfig.c
+++ b/Python/initconfig.c
@@ -63,7 +63,38 @@
-W arg : warning control; arg is action:message:category:module:lineno\n\
also PYTHONWARNINGS=arg\n\
-x : skip first line of source, allowing use of non-Unix forms of #!cmd\n\
--X opt : set implementation-specific option\n\
+-X opt : set implementation-specific option. The following options are available:\n\
+\n\
+ -X faulthandler: enable faulthandler\n\
+ -X showrefcount: output the total reference count and number of used\n\
+ memory blocks when the program finishes or after each statement in the\n\
+ interactive interpreter. This only works on debug builds\n\
+ -X tracemalloc: start tracing Python memory allocations using the\n\
+ tracemalloc module. By default, only the most recent frame is stored in a\n\
+ traceback of a trace. Use -X tracemalloc=NFRAME to start tracing with a\n\
+ traceback limit of NFRAME frames\n\
+ -X showalloccount: output the total count of allocated objects for each\n\
+ type when the program finishes. This only works when Python was built with\n\
+ COUNT_ALLOCS defined\n\
+ -X importtime: show how long each import takes. It shows module name,\n\
+ cumulative time (including nested imports) and self time (excluding\n\
+ nested imports). Note that its output may be broken in multi-threaded\n\
+ application. Typical usage is python3 -X importtime -c 'import asyncio'\n\
+ -X dev: enable CPython’s “development mode”, introducing additional runtime\n\
+ checks which are too expensive to be enabled by default. Effect of the\n\
+ developer mode:\n\
+ * Add default warning filter, as -W default\n\
+ * Install debug hooks on memory allocators: see the PyMem_SetupDebugHooks() C function\n\
+ * Enable the faulthandler module to dump the Python traceback on a crash\n\
+ * Enable asyncio debug mode\n\
+ * Set the dev_mode attribute of sys.flags to True\n\
+ * io.IOBase destructor logs close() exceptions\n\
+ -X utf8: enable UTF-8 mode for operating system interfaces, overriding the default\n\
+ locale-aware mode. -X utf8=0 explicitly disables UTF-8 mode (even when it would\n\
+ otherwise activate automatically)\n\
+ -X pycache_prefix=PATH: enable writing .pyc files to a parallel tree rooted at the\n\
+ given directory instead of to the code tree\n\
+\n\
--check-hash-based-pycs always|default|never:\n\
control how Python invalidates hash-based .pyc files\n\
";