Tells the compiler to translate #include directives for an importable header-name into an import header-name; directive, rather than use textual inclusion.

/translateInclude

The /translateInclude compiler option requires you enable experimental modules support by use of the /experimental:module compiler option, along with the /std:c++latest option. This option is available starting in Visual Studio 2019 version 16.8.

The /translateInclude option effectively makes the following transformation, where the example <vector> is an importable header unit:

#include <vector>

The compiler replaces this directive with:

import <vector> ;

In MSVC an importable header unit is one named by a /headerUnit reference. For more information, see /headerUnit (Use header unit IFC).

Given a project that references two header files and their header units, listed in this table:

And a source .cpp file that includes the headers,

#include "utils/util.h"
#include "app/app.h"

int main() { }

The /translateInclude option allows the compiler to import the header units instead of compile the headers again. Here's an example command line that translates the include directives for util.h and app.h into imports of the header units instead:

cl /IC:\ /experimental:module /translateInclude /headerUnit C:\utils\util.h=C:\util.h.ifc /headerUnit C:\app\app.h=C:\app.h.ifc

1. Open the project's Property Pages dialog box. For details, see Set C++ compiler and build properties in Visual Studio.

2. Set the Configuration drop-down to All Configurations.

3. Select the Configuration Properties > C/C++ > Command Line property page.

4. Modify the Additional Options property to add the /translateInclude option. Then, choose OK or Apply to save your changes.

/experimental:module (Enable module support)
/headerUnit (Use header unit IFC).
/module:exportHeader (Create header units)
/module:reference (Use named module IFC)