I may be right in front of my face but I don't see it. Can you send
a couple lines of what the link's error messages are like?
On May 5, 2006, at 4:29 PM, Brian Budge wrote:
Hi all -
I'm attempting to use gsl (gnu scientific library) from my C++
program. gsl is a C program, and I need to pass function pointers to
gsl to make it do it's magic on my data.
The problem I'm having stems from the fact that I need my functions to
be template functions.
I can get everything to compile, but I can't get it to link.
The gist is like this:
template<class Stencil>
int ll_uv_f(const gsl_vector *x, void *params, gsl_vector *f){
LL_uv_data<Stencil> *lld = static_cast< LL_uv_data<Stencil>* >
(params);
const real a = gsl_vector_get(x,0);
const real b = gsl_vector_get(x,1);
Vec v = lld->ll->eval(a, b) - lld->pt;
for(int i = 0; i < 2; ++i){
gsl_vector_set(f, i, v[i]);
}
return GSL_SUCCESS;
}
template<class Stencil>
int ll_uv_df(const gsl_vector *x, void *params, gsl_matrix *J){...}
template<class Stencil>
int ll_uv_fdf(const gsl_vector *x, void *params, gsl_vector *f,
gsl_matrix *J){...}
The calling function then contains the code:
LL_uv_data<BaseStencil> dat(Vec(u,v), this);
gsl_multiroot_function_fdf f = {ll_uv_f<BaseStencil>,
ll_uv_df<BaseStencil>,
ll_uv_fdf<BaseStencil>,
2, &dat};
I also explicitly instantiate the template functions for several
instances in a .cc file:
//explicit instantiation of template functions
template int ll_uv_fdf<CCStencil>(const gsl_vector *x, void *params,
gsl_vector *f, gsl_matrix *J);
template int ll_uv_fdf<BSStencil>(const gsl_vector *x, void *params,
gsl_vector *f, gsl_matrix *J);
.
.
.
template int ll_uv_df<CCStencil>(const gsl_vector *x, void *params,
gsl_matrix *J);
template int ll_uv_df<BSStencil>(const gsl_vector *x, void *params,
gsl_matrix *J);
.
.
.
template int ll_uv_f<CCStencil>(const gsl_vector *x, void *params,
gsl_vector *f);
template int ll_uv_f<BSStencil>(const gsl_vector *x, void *params,
gsl_vector *f);
.
.
.
The program compiles fine, and the functions int ll_uv_*() are found
by the nm utility to be in a .o file.
The program still won't link. Anyone have any ideas? Is this
something I'm doing wrong? The gcc version is 3.4.5-r1, and this is
on a xeon box running linux.
Thanks,
Brian
