Linking to a C++ .obj file

[foolcow]

I'm trying to figure out how to call a C++ function from Delphi 5.

In the implementation section of my .pas file, I have the following two lines:

{$L stringutil.obj}
function FirstDigitInString( strX: PChar ):Integer;external;

stringutil.obj contains a function which was declared as follows (In Borland C++ Builder 5):

int __stdcall FirstDigitInString( char *strX );

When I try to compile, I get the compiler error, "Unsatisfied forward or external declaration: "FirstDigitInString"

Does anybody know what I should do to solve this? [sig][/sig]