Eryk Sun added the comment: test_os intentionally operates on invalid file descriptors. In the Windows CRT this leads to failed assertions, such as from its _VALIDATE_RETURN macro. This macro would also call the default invalid parameter handler, which would kill the process, but that's disabled in 3.5+ via _Py_BEGIN_SUPPRESS_IPH. That leaves the message box for failed assertions in debug builds [1]. On entry, support.SuppressCrashReport calls the CRT functions _CrtSetReportMode [2] and _CrtSetReportFile [3] to ensure that failed assertions are instead printed to stderr. These functions are available in a debug build of the msvcrt module.
[1]: https://msdn.microsoft.com/en-us/library/9sb57dw4.aspx [2]: https://msdn.microsoft.com/en-us/library/1y71x448.aspx [3]: https://msdn.microsoft.com/en-us/library/a68f826y.aspx ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue27423> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
