# Fortran_PREPROCESS

Added in version 3.18.

Control whether the Fortran source file should be unconditionally preprocessed.

If unset or empty, rely on the compiler to determine whether the file should be preprocessed. If explicitly set to `OFF` then the file does not need to be preprocessed. If explicitly set to `ON`, then the file does need to be preprocessed as part of the compilation step.

When using the `Ninja` generator, all source files are first preprocessed in order to generate module dependency information. Setting this property to `OFF` will make `Ninja` skip this step.

Consider using the target-wide `Fortran_PREPROCESS` property if all source files in a target need to be preprocessed.