boost:::format will not compile under VC++ WITH "Microsoft language extensions"

[Jive Dadson <jdadson@…>]

Boost::format will not compile under Microsoft VC++ unless Microsoft Language Extensions (/Za) are turned OFF. When MS Language Extensions are turned ON, the compiler complains because boost overrides some virtual functions in std:: classes with functions lacking a "throw()" specifier. One of the functions is the destructor ~basic_streambuf().

I do not know if this is a bug or a misunderstanding on my part. If it is a bug, I do not know whether it is on the MS or boost side. However, it should be a simple matter to decorate those functions with "throw()." That could save someone a lot of trouble.

[Jive Dadson <jdadson@…>]

I asked about this on Stackoverflow. ​http://stackoverflow.com/questions/12764151/compiler-error-vc-2012-boostformat/12764654#12764654

[Jive Dadson <jdadson@…>]

Eratum: I should have said, "Boost::format will not compile under Microsoft VC++ unless Microsoft Language Extensions (/Za) are turned ON." I cannot find an "edit" button on the ticket.

[Michel Morin]

Don't use /Za.

The /Za option is buggy and you shouldn't use it. See the posts from Stephan T. Lavavej (Visual C++ libraries developer) such as ​this and ​this. Also, ​Boost's warning guidelines might be useful for you.

[Michel Morin]

Ah, I meant "don't turn off Microsoft Language Extensions."

[Jive Dadson <jdadson@…>]

I would like for the decision to close this item to be reviewed. I spent hours figuring out what was wrong. Others will too. Or give up. What could it hurt to add "throw()" to some functions that cannot throw an exception?

[Jive Dadson <jdadson@…>]

@James I tracked it down. The bug is in the VC++ header file The declaration for ~basic_streambuf() does not have a "throw()" exception-specifier. Section 27.6.3, C++11; Section 27.5.1 C++03. Nevertheless, boost could add it harmlessly. The destructor is on line 65 in alt_sstream_impl.hpp.

virtual ~basic_altstringbuf() throw() edit, j. dadson

{ dealloc(); }

[Jive Dadson]

I submitted a bug report to Microsoft. ​https://connect.microsoft.com/VisualStudio/feedback/details/766514/incorrect-exception-specifier-in-vc-header-file-causes-correct-user-code-not-to-compile#tabs - Jive

[claudiordgz]

I spent hours as well, the error appeared in ASIO (No Boost) in my case in error.ipp

const char* name() const ASIO_ERROR_CATEGORY_NOEXCEPT

and in error_code.ipp

const char* name() const ASIO_ERROR_CATEGORY_NOEXCEPT

For the moment I had to add the throw, but I feel filthy.

I think this error should be fixed from MS end, just my two cents.

[James E. King, III]

​https://github.com/boostorg/format/pull/21 merged into develop leaving open until merged into master