# PCH_WARN_INVALID

Added in version 3.18.

When this property is set to true, the precompile header compiler options will contain a compiler flag which should warn about invalid precompiled headers e.g. `-Winvalid-pch` for GNU compiler.

This property is initialized by the value of the `CMAKE_PCH_WARN_INVALID` variable if it is set when a target is created. If that variable is not set, the property defaults to `ON`.