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sys module

The module exposes only the attributes listed below; every other sys.* access raises AttributeError.

Attributes

  • sys.version — the string "3.14.0 (Monty)".
  • sys.version_info — named tuple (major=3, minor=14, micro=0, releaselevel='final', serial=0).
  • sys.hexversion — 0x030E00F0, the packed form of that version_info.
  • sys.api_version — 1013, CPython 3.14’s C API version. Monty has no C API, so nothing can be loaded against it; the number is reported only so version-gated code reads what it expects.
  • sys.argv — a one-element list holding the script name, with any host directory component stripped (['main.py']), so sys.argv[0] is what __file__ places under the working directory. Monty runs no command line, so there is never an argument after argv[0]; passing arguments from the host is not supported yet. The list is mutable as in CPython, but import builds a fresh module every time, so edits to it do not survive a second import sys (see modules.md).
  • sys.platform — the string "monty", not "linux" / "darwin" / "win32". Code that branches on the host OS will not work; the sandbox does not expose which OS it runs on.
  • sys.copyright — Monty’s copyright line, not CPython’s.
  • sys.builtin_module_names — every module Monty can import, since they are all compiled into the interpreter. CPython lists only its C modules, so the tuple differs: it includes json, re, typing and the other modules that are pure Python in CPython, and omits builtins, time and everything else Monty does not implement. See modules.md for the module list.
  • sys.maxsize — 2**63 - 1 on every target, including 32-bit wasm where the real container ceiling is lower. Resource limits bind long before either.
  • sys.maxunicode — 1114111 (U+10FFFF), as in CPython.
  • sys.byteorder — always "little"; Monty builds for no big-endian target.
  • sys.float_info — the IEEE 754 binary64 properties of the f64 Monty stores floats in, so the values match CPython. rounds is 1 (round-to-nearest) and nothing in the sandbox can change it.
  • sys.float_repr_style — always "short".
  • sys.executable, sys.prefix, sys.exec_prefix, sys.base_prefix, sys.base_exec_prefix — the empty string. The sandbox has no install tree, and CPython documents the empty string for a path it cannot determine. prefix == base_prefix, so the usual virtualenv test reports “not in one”.
  • sys.platlibdir — "lib", joined onto a sys.prefix that is empty.
  • sys.abiflags — the empty string; Monty has no ABI. CPython does not define this attribute at all on Windows.
  • sys.dont_write_bytecode — True, where CPython defaults to False. Monty never writes bytecode to disk.
  • sys.pycache_prefix — always None.
  • sys.flags — the same 18 fields CPython 3.14 reports, in the same order. Monty is started with no command line, so every switch reads 0 / False, including utf8_mode and safe_path even though the sandbox has no other encoding and no sys.path. Two fields describe Monty rather than an unset switch: dont_write_bytecode is 1, agreeing with sys.dont_write_bytecode, and hash_randomization is 0 because Monty seeds no hashes — CPython reports 1 by default. int_max_str_digits is 4300, the limit Monty enforces, but there is no sys.set_int_max_str_digits to change it. CPython 3.14 carries three further fields outside the sequence — gil, thread_inherit_context and context_aware_warnings, reachable by name but not by index and not counted by len(). They describe the GIL and thread-context machinery Monty does not have, so they raise AttributeError; the 18-element sequence itself matches CPython’s.
  • sys.stdout / sys.stderr — opaque marker objects with no methods. They cannot be written to via .write(), and sys.stdout.flush() and the rest raise AttributeError. They are useful only as print(..., file=...), which routes output to that stream through the host print callback (see print.md).

Accessing an attribute the module does not define raises Monty’s generic AttributeError: 'module' object has no attribute '<name>', where CPython says module 'sys' has no attribute '<name>'.

Not implemented

path, modules, exit, exc_info, getrecursionlimit, getsizeof, getrefcount, intern, displayhook, excepthook, settrace, setprofile, stdin, __stdout__, _getframe, audit.

hash_info, int_info and thread_info describe CPython’s own C implementation — its string and integer hashing, its bignum digit layout, its thread library — none of which Monty shares, so they raise AttributeError rather than reporting fabricated values. In particular hash_info cannot be used to predict Monty’s hashes, which differ from CPython’s (see builtins.md).

ps1 and ps2 are absent, so hasattr(sys, 'ps1') correctly reports that the sandbox is not an interactive prompt.

The private install-layout attributes _base_executable, _framework, _git, _home and _stdlib_dir are absent for the same reason as sys.prefix and friends: there is no install tree.

Production builds do not expose sys.setrecursionlimit. Test builds expose a lowering-only hook so shared fixtures can force deterministic recursion errors; it cannot raise the host-configured ceiling. See resource_limits.md.