Tells the compiler to create the header units specified by the input arguments. The compiler generates header units as IFC (.ifc) files.

/exportHeader /headerName:angle header-name
/exportHeader /headerName:quote header-name
/exportHeader full path to header file

The argument to /exportHeader is a /headerName command-line option that specifies the name, header-name, of the header file to export.

/exportHeader is available starting in Visual Studio 2019 version 16.10 Preview 2.

The /exportHeader compiler option requires you enable the /std:c++latest option.

One /exportHeader compiler option can specify as many header-name arguments as your build requires. You don't need to specify them separately.

The compiler implicitly enables the new preprocessor when this switch is used. That is, /Zc:preprocessor is added to the command line by the compiler if any form of /exportHeader is used on the command line. To opt out of the implicit /Zc:preprocessor, use: /Zc:preprocessor-

By default, the compiler doesn't produce an object file when a header unit is compiled. To produce an object file, specify the /Fo compiler option. For more information, see /Fo (Object File Name).

You may find it helpful to use the complementary option /showResolvedHeader. The /showResolvedHeader option prints an absolute path to the file the header-name argument resolves to.

/exportHeader can handle multiple inputs at once, even under /MP. We recommended you use /ifcOutput <directory> to create a separate .ifc file for each compilation.

To build a header unit such as <vector> might look like:

cl . . . /std:c++latest /exportHeader /headerName:angle vector

Building a local project header such as "utils/util.h" might look like:

cl . . . /std:c++latest /exportHeader /headerName:quote util/util.h

You normally shouldn't set this in the Visual Studio development environment. It is set by the build system.

/headerName (Build a header unit from the specified header)
/headerUnit (Use header unit IFC)
/reference (Use named module IFC)
/translateInclude (Translate include directives into import directives)