diff options
Diffstat (limited to 'src/lib/asiolink/asio_wrapper.h')
| -rw-r--r-- | src/lib/asiolink/asio_wrapper.h | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/src/lib/asiolink/asio_wrapper.h b/src/lib/asiolink/asio_wrapper.h new file mode 100644 index 0000000000..09f64a92de --- /dev/null +++ b/src/lib/asiolink/asio_wrapper.h @@ -0,0 +1,67 @@ +// Copyright (C) 2016 Internet Systems Consortium, Inc. ("ISC") +// +// This Source Code Form is subject to the terms of the Mozilla Public +// License, v. 2.0. If a copy of the MPL was not distributed with this +// file, You can obtain one at http://mozilla.org/MPL/2.0/. +#ifndef ASIO_WRAPPER_H +#define ASIO_WRAPPER_H 1 + +// !!! IMPORTANT !!!! +// This file must be included anywhere one would normally have included +// boost/asio.hpp. Until the issue described below is resolved in some +// other fashion asio.hpp should not be included other than through +// this file. +// +// The optimizer as of gcc 5.2.0, may not reliably ensure a single value +// returned by boost::system::system_category() within a translation unit +// when building the header only version of the boost error handling. +// See Trac #4243 for more details. For now we turn off optimization for +// header only builds the under the suspect GCC versions. +// +// The issue arises from in-lining the above function, which returns a +// reference to a local static variable, system_category_const. This leads +// to situations where a construct such as the following: +// +// {{{ +// if (ec == boost::asio::error::would_block +// || ec == boost::asio::error::try_again) +// return false; +// }}} +// +// which involve implicit conversion of enumerates to error_code instances +// to not evaluate correctly. During the implicit conversion the error_code +// instances may be assigned differeing values error_code:m_cat. This +// causes two instances of error_code which should have been equal to +// to not be equal. +// +// The problem disappers if either error handling code is not built header +// only as this results in a single definiton of system_category() supplied +// by libboost_system; or the error handling code is not optimized. +// +// We're doing the test here, rather than in configure to guard against the +// user supplying the header only flag via environment variables. +// +// We opened bugs with GNU and BOOST: +// +// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69789 +// https://svn.boost.org/trac/boost/ticket/11989 +// +// @todo Currently, 5.3.0 is the latest released versio of GCC. Version 6.0 is +// in development and will need to be tested. + +#define GNU_CC_VERSION (__GNUC__ * 10000 \ + + __GNUC_MINOR__ * 100 \ + + __GNUC_PATCHLEVEL__) + +#if (defined(__GNUC__) && \ + ((GNU_CC_VERSION >= 50200) && (GNU_CC_VERSION <= 50301)) \ + && defined(BOOST_ERROR_CODE_HEADER_ONLY)) +#pragma GCC push_options +#pragma GCC optimize ("O0") +#include <boost/asio.hpp> +#pragma GCC pop_options +#else +#include <boost/asio.hpp> +#endif + +#endif // ASIO_WRAPPER_H |