5.1 Sendmail Macro Access Functions

Built-in Function: string getmacro (string macro)

Returns the value of Sendmail macro macro. If macro is not defined, raises the e_macroundef exception.

Calling getmacro(name) is completely equivalent to referencing ${name}, except that it allows to construct macro names programmatically, e.g.:

  if getmacro("auth_%var") = "foo"
    …
  fi

Built-in Function: boolean macro_defined (string name)

Return true if Sendmail macro name is defined.

Notice, that if your MTA supports macro name negotiation²², you will have to export macro names used by these two functions using ‘#pragma miltermacros’ construct. Consider this example:

func authcheck(string name)
do
  string macname "auth_%name"
  if macro_defined(macname)
    if getmacro(macname)
      …
    fi
  fi
done

#pragma miltermacros envfrom auth_authen

prog envfrom
do
  authcheck("authen")
done

In this case, the parser cannot deduce that the envfrom handler will attempt to reference the ‘auth_authen’ macro, therefore the ‘#pragma miltermacros’ is used to help it.