What is a Exit Code? - Exit statuses

Exit statuses (or “Exit Codes”) are integers that are returned when an application exits. These exit statuses can be caused by either Minecraft, or the operating system in use. There is no differentiation that can be made as to which is responsible for the Exit code, but currently Minecraft does not use non-generic exit statuses.

Exit statuses are also OS-dependent integers unless set by Minecraft or another loaded library.

Some known Exit Codes - Exit statuses

Bug Tracker Issue Exit Code
MCL-90 139
MCL-148 -1073740777
MCL-148 -1073741819
MCL-6550 -805306369
MC-19437 134
MC-22165 -2147483645
MC-26428 225
MC-114339 -1073740940

General Exit Codes - Exit statuses

Exit Code Meaning OS
0 Success
-1 Failure
1 Failure
255 Fallback status (used when status > 255) OSX / Linux