Unimplemented function?

[Luis Carlos Busquets Pérez]

It seems that there is a regression in wine 1.3.28. Before bi-secting, I 
woul dlike to understand how that can happen. Apparently PlaChessV5.exe 
crashes due to:

wine: Call from 0x68215ca8 to unimplemented function 
msvcrt.dll._snwprintf_s, aborting


but when I look at the spec file, the function is defined:

@ varargs _snwprintf_s(ptr long long wstr) MSVCRT__snwprintf_s

and it exists in wcs.c

How is it that them it results as undefined?

Luis