I've been trying to write some Matlab Coder code that needs a bunch of coder.ceval calls to functions in mat.h and mex.h. I've come into a problem, however, because my 64-bit system defines the "size_t" macro as a "long unsigned int", meaning a "uint64" which is not suppoted by codegen. If I attempt to return size_t variables as int32 or uint32, I definitely get the wrong answer (specifically, that sizeof(double)=6, sizeof(char)=4, sizeof(int)=3, etc). Does this mean that the Matlab Coder flat-out does not support coder.ceval calls on 64-bit systems that define size_t as a long int? That seems fairly crippling.