The C RTL provides support for compiling applications to use file sizes and offsets that are 2 GB and larger. This is accomplished by allowing file offsets of 64-bit integers. The fseeko and ftello functions, which have the same behavior as fseek and ftell, accept or return values of type off_t, which allows for a 64-bit variant of off_t to be used. C RTL functions lseek, mmap, ftuncate, truncate, stat, fstat, and ftw can also accommodate a 64-bit file offset. The new 64-bit interfaces can be selected at compile time by defining the _LARGEFILE feature macro.