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Diffstat (limited to 'docs/library/sys.rst')
| -rw-r--r-- | docs/library/sys.rst | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/docs/library/sys.rst b/docs/library/sys.rst index 197efc8015..fa49a8edb2 100644 --- a/docs/library/sys.rst +++ b/docs/library/sys.rst @@ -52,6 +52,31 @@ Constants CPython mandates more attributes for this object, but the actual useful bare minimum is implemented in MicroPython. +.. data:: maxsize + + Maximum value which a native integer type can hold on the current platform, + or maximum value representable by MicroPython integer type, if it's smaller + than platform max value (that is the case for MicroPython ports without + long int support). + + This attribute is useful for detecting "bitness" of a platform (32-bit vs + 64-bit, etc.). It's recommended to not compare this attribute to some + value directly, but instead count number of bits in it:: + + bits = 0 + v = sys.maxsize + while v: + bits += 1 + v >>= 1 + if bits > 32: + # 64-bit (or more) platform + ... + else: + # 32-bit (or less) platform + # Note that on 32-bit platform, value of bits may be less than 32 + # (e.g. 31) due to peculiarities described above, so use "> 16", + # "> 32", "> 64" style of comparisons. + .. data:: modules Dictionary of loaded modules. On some ports, it may not include builtin |