[Insight-developers] VXLNumerics (vnl)

[Kent Williams]

On Friday 14 February 2003 01:15 pm, Bill Hoffman wrote:
> Hi,
>
> I am working on upgrading the vnl to the most recent vxl repository.
> It has been almost a year since the last upgrade.

Bill, there's a problem with building VXL with Cygwin that needs
probably be resolved both in Insight and in the VXL distribution
itself.

Summary: The configure script erroneously sets the
VCL_NEEDS_INLINE_INSTANTIATION preprocessor symbol to
1, when it should be zero for pretty much any version of GCC.

I tracked this down to the vcl configure script.  It uses a conftest.C pr=
ogram
that will fail (in a perfect world) at link time if a compiler requires i=
nline=20
instantiation of templated functions, in other words

template <class T> inline int test(T const *x) { return 0; }

requires a declaration, e.g.

int  test<char>(char const *x);

In order to force the compiler generate the code.

The problem is the conftest for this feature fails because of WinMain bei=
ng=20
undefined, which would seem to me to have nothing to do with=20
VCL_NEEDS_INLINE_INSTATIATION