The special REXX variable RC usually contains the return code from the TSO command. If the command abends or is not found, or if another error is detected, special return codes are set, and a descriptive message can be written to the standard error stream:

• -3 usually means that the TSO command was not found.
• Other negative numbers are usually abend codes. These should be accompanied by a message containing an abend reason code.
• 16 usually means that a processing error was encountered.