C++ Keywords: __feacpBreak

The __feacpBreak keyword is the same as __compileBreak but for the Front-End Auto-Complete Parser (FEACP). It is a keyword to the compiler (C1 or C1XX), but only for the purpose of ignoring its appearance in the token stream.

Detection of the __feacpBreak keyword causes FEACP to break to the debugger if the /Bd option is active or if the environment variable _FEACP_DEBUGBREAK exists (whatever its value). Without either of these preparations, the keyword is simply ignored.

The __feacpBreak keyword is ignored not only by the compiler but also by the product documentation. Microsoft barely documents even the existence of FEACP, and anyway leaves undocumented all of the various provisions that the compiler makes for its own debugging.