From QB64.org wiki
- returnCode% = _SHELLHIDE(externalCommand$)
- The literal or variable STRING externalCommand$ parameter can be any external command line or call to another program.
- QB64 can return codes sent by program modules when a specified code is added after END or SYSTEM.
- The code can be used to verify that a previous SHELL command was executed.
Example: Shelling to another QB64 program will return the exit code when one is set in the program that is run.
- Explanation: To set a program exit code use an INTEGER parameter value after END or SYSTEM in the called program.