4.26.1 Preprocessor Configuration

The preprocessor is configured in the mailfromd configuration file, using the preprocessor statement (see Preprocessor Configuration). The default settings correspond to the following configuration:

preprocessor {
  # Enable preprocessor
  enable yes;
  # Preprocessor command line stub.
  command "m4 -s";
  # Pass current include path to the preprocessor via -I options.
  pass-includes false;
  # Pass to the preprocessor the feature definitions via -D options
  # as well as any -D/-U options from the command line
  pass-defines true;
  # Name of the preprocessor setup file.  Unless absolute, it is
  # looked up in the include path.
  setup-file "pp-setup";
}

If pass-includes is true, the command value is augmented by zero or more -I options supplying it the mailfromd include search path (see include search path).

Furthermore, if pass-defines is set, zero or more -D options defining optional features are passed to it (e.g. -DWITH_DKIM) as well as any -D and -U options from the mailfromd command line.

Unless the value of setup-file begins with a slash, the file with this name is looked up in the current include search path. If found, its absolute name is passed to the preprocessor as first argument.

If it begins with a slash, it is passed to the preprocessor as is.