name : test_compile_flags.py ############################################################################## # # Copyright (c) 2022 Zope Foundation and Contributors. # All Rights Reserved. # # This software is subject to the provisions of the Zope Public License, # Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution. # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS # FOR A PARTICULAR PURPOSE # ############################################################################## import struct import unittest import zope.interface # noqa: try to load a C module for side effects class TestFloatingPoint(unittest.TestCase): def test_no_fast_math_optimization(self): # Building with -Ofast enables -ffast-math, which sets certain FPU # flags that can cause breakage elsewhere. A library such as BTrees # has no business changing global FPU flags for the entire process. zero_bits = struct.unpack("!Q", struct.pack("!d", 0.0))[0] next_up = zero_bits + 1 smallest_subnormal = struct.unpack("!d", struct.pack("!Q", next_up))[0] self.assertNotEqual(smallest_subnormal, 0.0)