Problem building cpp_dec_float multiprecision example

[magoni@…]

Dear developer,

I would like to build the small example shown at:

http://www.boost.org/doc/libs/1_56_0/libs/multiprecision/doc/html/boost_multiprecision/tut/floats/cpp_dec_float.html

But it fails to compile with MSVC 2008 on Windows 7:

1>Linking... 1>bmt.obj : error LNK2019: unresolved external symbol "class boost::multiprecision::number<class boost::multiprecision::backends::cpp_dec_float<100,int,void>,1> cdecl boost::math::tgamma<struct boost::multiprecision::detail::expression<struct boost::multiprecision::detail::multiply_immediates,class boost::multiprecision::number<class boost::multiprecision::backends::cpp_dec_float<100,int,void>,1>,class boost::multiprecision::number<class boost::multiprecision::backends::cpp_dec_float<100,int,void>,1>,void,void> >(struct boost::multiprecision::detail::expression<struct boost::multiprecision::detail::multiply_immediates,class boost::multiprecision::number<class boost::multiprecision::backends::cpp_dec_float<100,int,void>,1>,class boost::multiprecision::number<class boost::multiprecision::backends::cpp_dec_float<100,int,void>,1>,void,void>)" (??$tgamma@U?$expression@Umultiply_immediates@detail@multiprecision@boost@@V?$number@V?$cpp_dec_float@$0GE@HX@backends@multiprecision@boost@@$00@34@V534@XX@detail@multiprecision@boost@@@math@boost@@YA?AV?$number@V?$cpp_dec_float@$0GE@HX@backends@multiprecision@boost@@$00@multiprecision@1@U?$expression@Umultiply_immediates@detail@multiprecision@boost@@V?$number@V?$cpp_dec_float@$0GE@HX@backends@multiprecision@boost@@$00@34@V534@XX@detail@31@@Z) referenced in function _main 1>bmt.obj : error LNK2019: unresolved external symbol "class boost::multiprecision::number<class boost::multiprecision::backends::cpp_dec_float<100,int,void>,1> cdecl boost::math::tgamma<class boost::multiprecision::number<class boost::multiprecision::backends::cpp_dec_float<100,int,void>,1> >(class boost::multiprecision::number<class boost::multiprecision::backends::cpp_dec_float<100,int,void>,1>)" (??$tgamma@V?$number@V?$cpp_dec_float@$0GE@HX@backends@multiprecision@boost@@$00@multiprecision@boost@@@math@boost@@YA?AV?$number@V?$cpp_dec_float@$0GE@HX@backends@multiprecision@boost@@$00@multiprecision@1@V231@@Z) referenced in function _main 1>D:\Damien\Programmation\boost-multiprecision-test\Debug\boost-multiprecision-test.exe : fatal error LNK1120: 2 unresolved externals

And I don't understand why since it should be a header-only lib. Any help would be highly appreciated. Best regards,

[John Maddock]

Ah, there's an error in the example: a missing #include, you need to add

#include <boost/math/special_functions/gamma.hpp>

To the top of the example, I'll fix the docs shortly.

[John Maddock]

Fixed in ​https://github.com/boostorg/multiprecision/commit/cd1e62a4b0a42abf89eab2b2d1a1ecf3607b8c7e