Re: [Boost-users] Boost date time and MinGW

From: Jeff Garland (jeff_at_[hidden])
Date: 2007-02-25 11:44:11

Franck Guillaud wrote:

> 
> g++ -DUSE_DATE_TIME_PRE_1_33_FACET_IO -I"E:\dev\boost_1_33_1" -O0 -g3 
> -Wall -c -fmessage-length=0 -MMD -MP -MF"main.d" -MT"main.d" -o"main.o" 
> "../main.cpp"
> 
> g++ -L"E:\dev\boost_1_33_1\stage\lib" -o"TestBOOST.exe"  ./main.o 
> -lboost_date_time-mgw-mt-d-1_33_1
> 
> I get the error (simplified output) :
> 
> E:/dev/boost_1_33_1/boost/date_time/gregorian/greg_weekday.hpp:
> undefined reference to `boost::gregorian::greg_month::as_long_string() 
> const'
> 
> If I remove the lines with *to_simple_string*, I get no error.
> 
>  From the docs [*] it seems there may be a problem for streams support 
> for some compilers, so I tryed to define USE_DATE_TIME_PRE_1_33_FACET_IO 
> in my project, but with no effect. Does it needs to be done when 
> compiling boost ?
> 
>   Is there any other way to solve my link problem ?
>   (appart not using string output for dates :-)  )
> 
>   Thanks for any help.

Well, my guess is that somehow your -L option or the library name in the -l 
are incorrect.  The difference is that to_simple_string depends on the 
function you can't find from the library while most of the rest of date-time 
code is inline. When you remove that function all the rest of date-time is 
compiling inline and hence no linker error. There's no reason I'm aware of to 
use the PRE_1_33_FACET_IO with mingw so I'd recommend staying away from 
to_simple_string and just writing:

inline
std::string
my_simple_string(date d)  {
    std::stringstream ss;
    ss << d;
    return ss.str();
}

It's likely that as support for older compilers is dropped to_simple_string 
will be re-written in this fashion.

HTH,

Jeff