The default API output message protocol consists of two parts. First, a code is output indicating whether or not the API request succeeded or generated an error.
The code output is either the textual sequence
for a successful evaluation, or the sequence
if an error occurred during evaluation. This code can be used by the client application to interpret the second part of the output protocol.
Second, the result of the API request is output according to the SubL "print" protocol. More precisely, the SubL function PRINT is called on the result of the evaluation.
Thus, the result will be a textual sequence of the form
<API result> <whitespace>