++ERROR message

This directive outputs a message (as with ++MESSAGE) but also generates a compiler error. As with ++MESSAGE, it is mainly used in conjunction with Conditional Compilation (in which see Example 2) to make sure that the programmer doesn't overlook and important problem. Example:

++IF TARGET_PLATFORM = 1

   ++MESSAGE Compiling for platform Windows

++ELSE

   ++ERROR This program only supports Windows - must use /C:TARGET_PLATFORM=1

++ENDIF