- (open-input-file filename [mode ...])procedure
Takes a string naming an existing file and returns an input port capable of delivering characters from the file. If the file cannot be opened, an error is signalled.
Additional mode arguments can be passed in, which should be any of the keywords #:text or #:binary. These indicate the mode in which to open the file (this has an effect on non-UNIX platforms only). The extra mode arguments are CHICKEN extensions to the R5RS standard.