# ++ERROR
> [HTML Version](error_compiler.htm)
**\++ERROR _message_ **
This directive outputs a message (as with ++MESSAGE) but also generates a compiler error. Like ++MESSAGE, it is mainly used in conjunction with [Conditional Compilation](conditionalcompilation.htm.md) (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