keyring: getstring, putstring, getbytearray, putbytearray, puterror - exchange data on delimited streams .EX 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; These functions provide I/O for strings, byte arrays and error strings over network connections that provide a record structure for communication (as provided for arbitrary networks by ssl (3)).

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.

/libinterp/keyring.c The output functions return an int which is -1 if there was an I/O error, and a non-negative value otherwise. The input functions return a tuple that includes a string indicating the cause of the error, as the second element of the tuple.