Unloading programs

The UNLOAD-ALLOWED operand allows the user to determine whether the program loaded at execution time can be unloaded.
If an attempt is made to unload a program when it is not allowed, an error occurs.

If the program cannot be unloaded (UNLOAD-ALLOWED = *NO), no command that unloads a program can be called during procedure execution.

Such a command would be, for example, START-EXECUTABLE-PROGRAM, which starts up a program. However, only one program can be loaded at any one time. If another program is already loaded, it is first unloaded, before the second program is loaded and started up with START-EXECUTABLE-PROGRAM.