$ZC[STATUS] holds the value of the status code for the last compilation performed by a ZCOMPILE, ZLINK or auto-ZLINK . One (1) indicates a clean compilation, a positive number greater than one is an error code you can turn into text with $ZMESSAGE(), and a negative number is a negated error code that indicates GT.M was not able to produce an object file. The error details appear in the compilation output, so $ZCSTATUS typically contains the code for ERRORSUMMARY.

GT.M does not permit the SET command to modify $ZCSTATUS.