example, a \class{c{\_}char{\_}p} item in the \member{argtypes} tuple will
convert a unicode string passed as argument into an byte string
using ctypes conversion rules.
+
+New: It is now possible to put items in argtypes which are not
+ctypes types, but each item must have a \method{from{\_}param} method
+which returns a value usable as argument (integer, string, ctypes
+instance). This allows to define adapters that can adapt custom
+objects as function parameters.
\end{memberdesc}
\begin{memberdesc}{errcheck}