On a modern POSIX environment, you can hack together an approximation of an overlay by loading some code to an area of memory, mprotect( ptr, len, PROT_EXEC) th

On a modern POSIX environment, you can hack together an approximation of an overlay by loading some code to an area of memory, mprotect( ptr, len, PROT_EXEC) the segment, ((int(*)())ptr)() to call the function and if you did everything right, you don't segfault too hard. Later, you can overwrite that area of memory with other code and repeat. This is similar to what actually goes on under the hood of the dynamic loader. http://tldp.org/HOWTO/Program-Library-HOWTO/dl-libraries.html http://tldp.org/HOWTO/Program-Library-HOWTO/dl-libraries.htm...