Based on R6RS.
status: final (2020-07-31)
keywords: I/OSee also SRFI 181: Custom ports (including transcoded ports).
This is an extract from the R6RS that documents its support for positioning ports. Binary ports can be positioned to read or write at a specific byte; textual ports at a specific character, although character positions can't be synthesized portably. It has been lightly edited to fit R7RS style.