Re: [boost] Win64 and abi_prefix.hpp/abi_suffix.hpp warnings

Subject: Re: [boost] Win64 and abi_prefix.hpp/abi_suffix.hpp warnings
From: Chris Newbold (Chris.Newbold_at_[hidden])
Date: 2008-09-25 10:51:59

> From: boost-bounces_at_[hidden] [mailto:boost-bounces_at_[hidden]]
> On Behalf Of Chris Newbold
> Sent: Thursday, September 25, 2008 10:35 AM

> Assuming that's the case, I would like to propose adding a warning
> suppression to config/warning_disable.hpp to silence this particular
> warning. Here's a diff of what I'm proposing:
>
> @@ -43,5 +43,14 @@
>     // std library function is encountered.
>  #  pragma warning(disable:1786)
>  #endif
> +#if defined(_MSC_VER) && defined(_M_X64)
> +   // warning: 'file': alignment changed after including header, may
> +   // be due to missing #pragma pack(pop)
> +   //
> +   // Caused by MSVC-specific abi_prefix and abi_suffix bookends which
> +   // twiddle the default structure alignment via #pragma pack(); this
> +   // results in a warning only on x86_64 targets.
> +#  pragma warning(disable:4103)
> +#endif
>
>  #endif // BOOST_CONFIG_WARNING_DISABLE_HPP

Of course that doesn't work, because warning_disable.hpp isn't universally included. My bad.

Here's an alternate proposal that does work: add a warning suppression to config/abi/msvc_prefix.hpp:

@@ -3,6 +3,18 @@
 //  Boost Software License, Version 1.0. (See accompanying file
 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

+#if defined(_M_X64)
+   // warning: 'file': alignment changed after including header, may
+   // be due to missing #pragma pack(pop)
+   //
+   // Changing the default structure alignment across header file
+   // boundaries causes a warning on the x86_64 target. Unfortunately,
+   // there is no way to do a push-pop on the state of this warning
+   // since popping it back to the 'on' state results in a warning as
+   // the compiler exits the suffix file
+#  pragma warning(disable:4103)
+#endif
+
 #pragma pack(push,8)

Does this seem reasonable?

-Chris