How difficult the program is to port all depends on the program. If the program uses strickly ANSI C or C++ functions there should be few if any porting problems. But most programs use some hardware-specific functions. You will just have to take them one at a time. First attempt to compile with the compiler on MAC computer then fix up whatever errors that compiler spits out. In some cases you might need to do major rewrite of the program, or parts of the program. I know little, if anything, about MAC, so can't really help you any more. I do know, however, end-of-line terminator on MAC file system is not the same as MS-Windows, MS-DOS or *nix. So if your program has hardcoded "\n" or "\r\n", then you will have to change it to "\r". If the program used a macro for eol sequence then that port will be trivel.