mutiple template definitions when linking

[Richard Forrest]

Compiler: gcc-4.3.2
Platform: Ubuntu linux
Boost version: 1.43

When linking two separately compiled object files that both include <boost/fcgi.hpp>, the link fails with:

MenuModule.o:/usr/include/boost/cgi/fcgi/client.hpp:157: first defined here
Menu.o: In function `boost::cgi::common::basic_client<boost::cgi::common::tags::fcgi>::handle_write(unsigned int, boost::system::error_code&)':
/usr/include/boost/cgi/fcgi/client.hpp:157: multiple definition of `boost::cgi::common::basic_client<boost::cgi::common::tags::fcgi>::handle_write(unsigned int, boost::system::error_code&)'

etc....

The problem seems to be that fully specialized versions of template functions should be declared as inline. Not doing so causes a version to exist in each compilation unit.

I inlined the ones that seemed to be causing the linking problem.

e.g. in boost/cgi/fcgi/client.hpp

  template<>
inline <--------------------- Added by me!
  void
  basic_client<
      ::BOOST_CGI_NAMESPACE::common::tags::fcgi
  >::handle_write(std::size_t bytes_transferred, boost::system::error_code& ec)

That seemed to fix it.

There are a few more in that file which I also needed to inline. Probably there are others in other files but they have not caused me problems.

Best regards, Richard

P.S. This is a really cool library. Thanks for all your hard work.

[Darren Garvey (darren-garvey)]

Hi Richard,

Thanks for the report.

The test suite is currently missing an automated test for multiple
translation units, which is why this was missed. I tested this within the
last couple of months, so I think this should be the only broken class, but
I'll apply this fix and add a test case for it this evening / or tomorrow.

Cheers,
Darren

P.S. The launchpad site isn't kept up to date - http://cgi.sf.net is the
main site for the library these days!

On 5 July 2010 13:32, Richard Forrest <email address hidden> wrote:

> Public bug reported:
>
>
> Compiler: gcc-4.3.2
> Platform: Ubuntu linux
> Boost version: 1.43
>
>
> When linking two separately compiled object files that both include
> <boost/fcgi.hpp>, the link fails with:
>
> MenuModule.o:/usr/include/boost/cgi/fcgi/client.hpp:157: first defined here
> Menu.o: In function
> `boost::cgi::common::basic_client<boost::cgi::common::tags::fcgi>::handle_write(unsigned
> int, boost::system::error_code&)':
> /usr/include/boost/cgi/fcgi/client.hpp:157: multiple definition of
> `boost::cgi::common::basic_client<boost::cgi::common::tags::fcgi>::handle_write(unsigned
> int, boost::system::error_code&)'
>
> etc....
>
> The problem seems to be that fully specialized versions of template
> functions should be declared as inline. Not doing so causes a version to
> exist in each compilation unit.
>
> I inlined the ones that seemed to be causing the linking problem.
>
> e.g. in boost/cgi/fcgi/client.hpp
>
> template<>
> inline <--------------------- Added by me!
> void
> basic_client<
> ::BOOST_CGI_NAMESPACE::common::tags::fcgi
> >::handle_write(std::size_t bytes_transferred, boost::system::error_code&
> ec)
>
> That seemed to fix it.
>
> There are a few more in that file which I also needed to inline.
> Probably there are others in other files but they have not caused me
> problems.
>
> Best regards, Richard
>
> P.S. This is a really cool library. Thanks for all your hard work.
>
> ** Affects: cgi
> Importance: Undecided
> Status: New
>
> --
> mutiple template definitions when linking
> https://bugs.launchpad.net/bugs/601886
> You received this bug notification because you are the registrant for
> Fast/CGI.
>