117 lines
3.3 KiB
ReStructuredText
117 lines
3.3 KiB
ReStructuredText
:mod:`sys` -- system specific functions
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========================================
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.. include:: ../templates/unsupported_in_circuitpython.inc
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.. module:: sys
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:synopsis: system specific functions
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|see_cpython_module| :mod:`cpython:sys`.
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Functions
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---------
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.. function:: exit(retval=0, /)
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Terminate current program with a given exit code. Underlyingly, this
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function raise as `SystemExit` exception. If an argument is given, its
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value given as an argument to `SystemExit`.
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Constants
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---------
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.. data:: argv
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A mutable list of arguments the current program was started with.
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.. data:: byteorder
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The byte order of the system (``"little"`` or ``"big"``).
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.. data:: implementation
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Object with information about the current Python implementation. For
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CircuitPython, it has following attributes:
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* *name* - string "circuitpython"
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* *version* - tuple (major, minor, micro), e.g. (1, 7, 0)
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This object is the recommended way to distinguish CircuitPython from other
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Python implementations (note that it still may not exist in the very
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minimal ports).
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.. admonition:: Difference to CPython
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:class: attention
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CPython mandates more attributes for this object, but the actual useful
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bare minimum is implemented in CircuitPython.
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.. data:: maxsize
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Maximum value which a native integer type can hold on the current platform,
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or maximum value representable by CircuitPython integer type, if it's smaller
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than platform max value (that is the case for CircuitPython ports without
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long int support).
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This attribute is useful for detecting "bitness" of a platform (32-bit vs
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64-bit, etc.). It's recommended to not compare this attribute to some
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value directly, but instead count number of bits in it::
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bits = 0
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v = sys.maxsize
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while v:
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bits += 1
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v >>= 1
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if bits > 32:
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# 64-bit (or more) platform
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...
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else:
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# 32-bit (or less) platform
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# Note that on 32-bit platform, value of bits may be less than 32
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# (e.g. 31) due to peculiarities described above, so use "> 16",
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# "> 32", "> 64" style of comparisons.
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.. data:: modules
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Dictionary of loaded modules. On some ports, it may not include builtin
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modules.
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.. data:: path
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A mutable list of directories to search for imported modules.
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.. data:: platform
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The platform that CircuitPython is running on. For OS/RTOS ports, this is
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usually an identifier of the OS, e.g. ``"linux"``. For baremetal ports it
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is an identifier of the chip on a board, e.g. ``"MicroChip SAMD51"``.
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It thus can be used to distinguish one board from another.
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If you need to check whether your program runs on CircuitPython (vs other
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Python implementation), use `sys.implementation` instead.
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.. data:: stderr
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Standard error ``stream``.
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.. data:: stdin
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Standard input ``stream``.
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.. data:: stdout
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Standard output ``stream``.
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.. data:: version
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Python language version that this implementation conforms to, as a string.
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.. data:: version_info
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Python language version that this implementation conforms to, as a tuple of ints.
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.. admonition:: Difference to CPython
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:class: attention
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Only the first three version numbers (major, minor, micro) are supported and
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they can be referenced only by index, not by name.
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