8.4.1 Implementation Defined Options

THROW-codes used in the system:

The codes -256−-511 are used for reporting signals. The mapping from OS signal numbers to throw codes is -256−signal. The codes -512−-2047 are used for OS errors (for file and memory allocation operations). The mapping from OS error numbers to throw codes is -512−errno. One side effect of this mapping is that undefined OS errors produce a message with a strange number; e.g., -1000 THROW results in Unknown error 488 on my system.