Indexes have type size_t, an unsigned integral type defined by your compiler, usually in <stddef.h>. Because size_t is unsigned, it allows 2n minus one, where n is the number of bits the size_t type has on your system.

Invalid indexes are signified by the special value RW_NPOS, defined in <rw/defs.h>.

When programming, you may need to know the specific version number of the Essential Tools Module to perform certain operations. This number is given by the macro RWTOOLS, expressed as a hexadecimal number. For example, version 1.2.3 would be 0x123. This can be used for conditional compilations.

If the version is needed at run time, you can find it via the function rwToolsVersion(), declared in header file <rw/tooldefs.h>.