On AIX, the locale encoding may be "iso8859-1", which was not a known syntax of
the legacy ISO 8859-1 encoding.

Using a C codec instead of a Python codec is faster but also avoids tricky
issues during Python startup or complex code.

_ctypes_alloc_format_string() failure

allocation failure

PyByteArray_FromStringAndSize() failure (ex: on memory allocation failure)

_PyBytes_Resize(&new) sets new to NULL on error, don't call Py_DECREF() with NULL.

ZIP archive.

memory allocation failure

exceptions when merging fast locals into f_locals of a frame.
PyEval_GetLocals() now raises an exception and return NULL on failure.

The underlying C libraries provide no mechanism for serializing compressor and
decompressor objects, so actually pickling these classes is impractical.
Previously, these objects would be pickled without error, but attempting to use
a deserialized instance would segfault the interpreter.

The underlying C libraries provide no mechanism for serializing compressor and
decompressor objects, so actually pickling these classes is impractical.
Previously, these objects would be pickled without error, but attempting to use
a deserialized instance would segfault the interpreter.

finalization.

sys.argv is set to None during Python finalization: add PyList_Check() to avoid
a crash in PyList_Size().

screen refresh problem.

pseudo-random number generator on fork().