[Libmesh-users] undefined reference to `exact_solution(double, double, double)'

[liang c. <goe...@gm...>]

Hi developers and users,

I completed an input script, which is a 1st-order time dependent PDE
including 2 equations and 2 variables. Then I generated this error when link
the program. I have checked my codes with ex9 & ex11 a couple of times, but
still can't get the code work.

The problem may lie in the 'exact_solution' function, I have define it
before main code as "Real exact_solution (const Real x,const Real y,const
Real t);" did I miss some head files?

Thanks!

Liang

========================================================

liang@b356:~/Desktop/libmesh/examples/lc2d_v1$ make
Compiling C++ (in debug mode) lc2d_v1.C...
Linking lc2d_v1-dbg...
lc2d_v1.x86_64-unknown-linux-gnu.dbg.o: In function `exact_value(Point
const&, Parameters const&, std::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&, std::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&)':
/home/liang/Desktop/libmesh/examples/lc2d_v1/lc2d_v1.C:58: undefined
reference to `exact_solution(double, double, double)'
lc2d_v1.x86_64-unknown-linux-gnu.dbg.o: In function
`assemble_lc(EquationSystems&, std::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&)':
/home/liang/Desktop/libmesh/examples/lc2d_v1/lc2d_v1.C:355: undefined
reference to `exact_solution(double, double, double)'
collect2: ld returned 1 exit status
make: *** [lc2d_v1-dbg] Error 1