External Functions: Alternative Method to use .dll from a C-script - modelica

Question

This is a companion question to External Functions: Reference headers in C-script to compiled dll.
That stack overflow question is using a Modelica external function call to a c-script. That c-script then uses c-functions contained within a .dll. Below is the initial preferred method I had attempted and a working attempt that I do not prefer.
Initial Attempt:
The following code would not work. My assumption was since I loaded the .dll Library libgsl in Modelica I could then simply use headers in the C-script to use function calls from that .dll. However, the dslog.txt file indicated that it couldn't recognize gsl_sf_bessel_j0. Apparently, the C-script doesn't know anything about the libgsl.dll that I specified in Modelica.
Modelica Function:
function chirp
input Modelica.SIunits.AngularVelocity w_start;
input Modelica.SIunits.AngularVelocity w_end;
input Real A;
input Real M;
input Real t;
output Real u "output signal";
external "C" u=chirp(w_start,w_end,A,M,t)
annotation(Library="libgsl", Include="#include \"chirp.c\"");
end chirp;
C-Script:
#include <gsl/gsl_sf_bessel.h>
double chirp2(double w1, double w2, double A, double M, double time)
{
double res;
double y;
res=A*cos(w1*time+(w2-w1)*time*time/(2*M));
y = gsl_sf_bessel_j0(res);
return y;
}
Working Attempt:
In order to use a .dll in an external function call using a C-script I found it necessary to independently load the library using the LoadLibrary command.
Is this method really necessary? This is much more complicated that my initial attempt I hoped would work where I was thinking Modelica contained the necessary "know-how" to load the .dll.
Bonus: It appears there exists a way to send error messages back to Modelica. void ModelicaVFormatError(const char* string, va_list). Know of a reference example of its usage so I can replace the printf statements which don't seem to send anything back to Modelica?
Modelica Function:
function chirp
input Modelica.SIunits.AngularVelocity w_start;
input Modelica.SIunits.AngularVelocity w_end;
input Real A;
input Real M;
input Real t;
input String fileName= Modelica.Utilities.Files.loadResource("modelica://ExternalFuncTest/Resources/Library/libgsl.dll") "Full file name for GSL library";
output Real u "output signal";
external "C" u=chirp(w_start,w_end,A,M,t)
annotation(Include="#include \"chirp.c\""); // <-- Removed Library reference
end chirp;
C-Script:
#include <windows.h>
#include <stdio.h>
typedef double (__cdecl *BESSEL)(const double);
double chirp3(double w1, double w2, double A, double M, double time, const char* fileName)
{
HINSTANCE hinstLib;
BESSEL bessel_J0;
BOOL fFreeResult, fRunTimeLinkSuccess = FALSE;
// Get a handle to the DLL module.
hinstLib = LoadLibrary(fileName);
// If the handle is valid, try to get the function address.
double res;
double y = 0;
res=A*cos(w1*time+(w2-w1)*time*time/(2*M));
if (hinstLib != NULL)
{
bessel_J0 = (BESSEL) GetProcAddress(hinstLib, "gsl_sf_bessel_j0");
// If the function address is valid, call the function.
if (NULL != bessel_J0)
{
fRunTimeLinkSuccess = TRUE;
printf("Success loading library method.\n"); //<-- Alternative to send message back to Modelica log file?
y = bessel_J0(res);
} else
{
printf("Failed to load library\n"); //<-- Alternative to send message back to Modelica log file?
}
// Free the DLL module.
fFreeResult = FreeLibrary(hinstLib);
}
return y;
}