On Sun, Nov 28, 2004 at 10:49:07PM +0100, Maciej Sobczak wrote:
Hi,
$ g++ --version g++ (GCC) 3.4.2 [FreeBSD] 20040728
(boost version 1.32)
When compiling a very simple example for the regex library, I've got the following error:
In file included from /usr/local/include/boost_1_32_0/boost/regex/v4/regex.hpp:99, from /usr/local/include/boost_1_32_0/boost/regex.hpp:34, from regex.cc:1: /usr/local/include/boost_1_32_0/boost/regex/v4/instances.hpp:71: error: ISO C++ forbids the use of `extern' on explicit instantiations *** Error code 1
Where you compiling with -pedantic ? AFAIK all versions of GCC reject this with -pedantic, but otherwise allow it as a GNU extension.
IMHO (and rather guessing), the #define in (*) is performed unnecessarily for g++ 3.4.2, but is executed just because of too generic __GNUC__ a little bit higher.
libstdc++ uses _GLIBCXX_EXTERN_TEMPLATE (or _GLIBCPP_EXTERN_TEMPLATE) in bits/istream.tcc to test whether to use the extern template syntax. That should probably be used by Boost.Regex too. jon -- This space left intentionally blank.