API function won't compile using CYGWIN g++; Interpreting error message

I'm using CYGWIN g++. I'm having trouble making an API call the
WindowFromPoint function.
Here is my code.
FILE: t.cc
#include <windows.h>
int main () {

POINT p;
p.x=200;
p.y=200;

HWND window_handle;

window_handle = WindowFromPoint(p);

return 0;
}
Here is the error message I'm getting:

C:\DOCUME~1\jeff\LOCALS~1\Temp\ccIIB5F0.o(.text+0 x22):t.cc: undefined
reference to 'WindowFromPoint@8'

Could someone please tell me
1)What this error means, specifically, and;

2)What I need to do to fix it

Thank you
Jeff

I'm using CYGWIN g++. I'm having trouble making an API call the
WindowFromPoint function.
Here is my code.
FILE: t.cc
#include <windows.h>
int main () {

POINT p;
p.x=200;
p.y=200;

HWND window_handle;

window_handle = WindowFromPoint(p);

return 0;
}
Here is the error message I'm getting:

C:\DOCUME~1\jeff\LOCALS~1\Temp\ccIIB5F0.o(.text+0x 22):t.cc: undefined
reference to 'WindowFromPoint@8'

Could someone please tell me
1)What this error means, specifically, and;
Although it's not a C problem as it's commonly discussed here, I *can* think
it's a linkage problem.
The linker can't resolve this name (WindowFromPoint) because you didn't
specify to your linker the library in which this function is stored.
2)What I need to do to fix it

I'm using CYGWIN g++. I'm having trouble making an API call the
WindowFromPoint function.
Here is my code.

FILE: t.cc
sounds like a C++, not C program.
#include <windows.h>
definitely non-standard header.
int main () {

POINT p;
undefined type POINT
p.x=200;
p.y=200;

HWND window_handle;
Undefined type HWND. declaring variable after executable code.

window_handle = WindowFromPoint(p);
Undeclared function.

return 0;
}
Here is the error message I'm getting:

C:\DOCUME~1\jeff\LOCALS~1\Temp\ccIIB5F0.o(.text+0x 22):t.cc: undefined
reference to 'WindowFromPoint@8'
Now we know you are using a C++ compiler. Off topic on c.l.c

Could someone please tell me
1)What this error means, specifically, and;

2)What I need to do to fix it