In order to support large files (i.e. those > 2GiB), a new type has been introduced into the BT library, BTint, which can be 32 bits (i.e int) when compiled without Large File Support, or 64 bits (i.e. long long), when compiled with Large File Support. BTint is a typedef, which will be declared as appropriate. BT library function arguments which must be declared as BTint are described in the API, but existing users of bfndky, bdbug, binsky, bnxtky or bupdky should be aware of the need to change argument declarations from int to BTint.