error(9P) - Plan 9 from User Space

| ERROR(9P) | ERROR(9P)
| NAME
| error – return an error
SYNOPSIS
| size[4] `Rerror` tag[2] ename[s]
DESCRIPTION
| The `Rerror` message (there is no `Terror`) is used to return an error string describing the failure of a transaction. It replaces the corresponding reply message that would accompany a successful call; its tag is that of the failing request.
By convention, clients may truncate error messages after `ERRMAX−1` bytes; `ERRMAX` is defined in `<libc.h>`.