Far pointers are for accessing memory in different segments. They're basically obsolete now. They were necessary in older machines with limited sized pointers or address spaces.

GCC still supports `__seg_fs` and `__seg_gs`, which behave similar to `far` in the example on the wiki page, as the FS and GS segment registers are still valid in x86-64 and used for TLS. Clang uses attributes `address_space(257)` and `address_space(256)` for the same thing.

The `__based` pointer in MSVC exploits the addressing modes by pinning the base in eg: `[base+index*scale+displacement]`. It's unrelated to segmentation.