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No, an int is 32bit on both 32bit and 64bit architectures. On windows even a long is still 32bit on 64bit, though on 64bit linux a long changes from 32bit to 64bit.
Integers are really only a problem if you try to store pointers in them, and that is a really odd sick thing to do.
You have much more problem with updating system-calls, and wierd interfaces that changes API depending on the architecture (like ODBC).