include "keyring.m"
keyring:= load Keyring Keyring->PATH;

getstring:    fn(fd: ref Sys->FD): (string, string);
putstring:    fn(fd: ref Sys->FD, s: string): int;
getbytearray: fn(fd: ref Sys->FD): (array of byte, string);
putbytearray: fn(fd: ref Sys->FD, a: array of byte, n: int): int;
puterror:     fn(fd: ref Sys->FD, s: string): int;

Putstring writes string s to fd. It returns the number of bytes written, or -1 if an error occurred. Messages written by putstring are truncated to 4096 bytes.

Getstring reads a string as written by putstring from fd and returns a tuple (result,error). If successful, the error string is nil.

Putbytearray writes the array of bytes a to fd. It returns the number of bytes written, or -1 if an error occurred. Messages written by putbytearray are truncated to 4096 bytes.

Getbytearray reads an array of bytes as written by putbytearray from fd and returns a tuple of the form (result,error). If successful, the error string is nil.

Puterror writes an error string s to fd. It can be used in place of putstring or putbytearray to cause a corresponding getstring or getbytearray to fail (in the receiving process), forcing them to return the error string s. It may not be longer than Sys->ERRMAX bytes.