The I/O port API of the Revised Report^6 on the Algorithmic Language Scheme (R6RS) is provided by the (rnrs
io ports) module. It provides features, such as binary I/O and Unicode
string I/O, that complement or refine Guile's historical port API
presented above (see Input and Output).
Note: The implementation of this R6RS API is currently far from complete, notably due to the lack of support for Unicode I/O and strings.