To elaborate a little:
function [ z ] = psi_nds_multiply( x, y )
z = x * y;
end
>> codegen -config:lib psi_nds_multiply
CRL: "ANSI_C" cannot be found in the registry.
Use help codegen for more information on using this command.
Error using codegen
The above function (in a file called psi_nds_multiply.m), fails to codegen with the above error.