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Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/library/os.rst | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/Doc/library/os.rst b/Doc/library/os.rst index e6b6465..785b080 100644 --- a/Doc/library/os.rst +++ b/Doc/library/os.rst @@ -3733,14 +3733,21 @@ Miscellaneous Functions This function returns random bytes from an OS-specific randomness source. The returned data should be unpredictable enough for cryptographic applications, - though its exact quality depends on the OS implementation. On a Unix-like - system this will query ``/dev/urandom``, and on Windows it will use - ``CryptGenRandom()``. If a randomness source is not found, + though its exact quality depends on the OS implementation. + + On Linux, ``getrandom()`` syscall is used if available and the urandom + entropy pool is initialized (``getrandom()`` does not block). + On a Unix-like system this will query ``/dev/urandom``. On Windows, it + will use ``CryptGenRandom()``. If a randomness source is not found, :exc:`NotImplementedError` will be raised. For an easy-to-use interface to the random number generator provided by your platform, please see :class:`random.SystemRandom`. + .. versionchanged:: 3.5.2 + On Linux, if ``getrandom()`` blocks (the urandom entropy pool is not + initialized yet), fall back on reading ``/dev/urandom``. + .. versionchanged:: 3.5 On Linux 3.17 and newer, the ``getrandom()`` syscall is now used when available. On OpenBSD 5.6 and newer, the C ``getentropy()`` |