Exit status

Tractor also scans for this directive:

TR_EXIT_STATUS nnn
ALF_EXIT_STATUS nnn

The integer nnn is used to determine success or failure rather than the actual program exit status. This override is most often used to express that an job-blocking error has occurred from within a library, even if the calling application is known to exit with status code zero. (0 indicates successful completion, any non-zero value indicates failure and results in a blocking task error). Conversely, some wrapper scripts will emit a zero code this way when the launched app is known to exit with a non-zero code in non-fatal cases. All legal application exit codes are are integers between 0 and 255 inclusive. Tractor will report exits due to interrupting signals using a negative number, namely the negative signal value. When tractor.config is configured to enable automatic task retries on error, all non-zero exit codes will cause a retry to occur except -2, -15, and -9 which are considered to be intentionally terminal due to user action. Note that if an application issues TR_EXIT_STATUS but does not actually exit within two seconds, then tractor-blade will automatically begin shutting down the application process group; this automatic sweep can be disabled in blade.config by adding this profile entry: "TR_EXIT_STATUS_termination": 0