title | description | ms.date | f1_keywords | helpviewer_keywords | ||||
---|---|---|---|---|---|---|---|---|
/reference (Use named module IFC) |
Use the /reference compiler option to create module header units for the header-name or include files specified. |
02/17/2022 |
|
|
Tells the compiler to use an existing IFC (.ifc
) for the current compilation.
/reference
module-name=filename
/reference
filename
filename
The name of a file that contains IFC data, which is prebuilt module information. To import more than one module, include a separate /reference
option for each file.
module-name
A valid name of an exported primary module interface unit name or full module partition name.
In most cases, you won't need to specify this switch because the project system discovers module dependencies within a solution automatically.
The /reference
compiler option requires you enable the /std:c++20
or later compiler option (such as /std:c++latest
). The /reference
option is available starting in Visual Studio 2019 version 16.10.
If the /reference
argument is a filename
without a module-name
, the file gets opened at runtime to verify the filename
argument names a specific import. It can result in slower runtime performance in scenarios that have many /reference
arguments.
The module-name
must be a valid primary module interface unit name or full module partition name. Examples of primary module interface names include:
M
M.N.O
MyModule
my_module
Examples of full module partition names include:
M:P
M.N.O:P.Q
MyModule:Algorithms
my_module:algorithms
If a module reference is created using a module-name
, other modules on the command line don't get searched if the compiler encounters an import of that name. For example, given this command line:
cl ... /std:c++latest /reference m.ifc /reference m=n.ifc
In the case above, if the compiler sees import m;
then m.ifc
doesn't get searched.
Given three modules as listed in this table:
Module | IFC file |
---|---|
M |
m.ifc |
M:Part1 |
m-part1.ifc |
Core.Networking |
Networking.ifc |
The reference options using a filename
argument would be like this:
cl ... /std:c++latest /reference m.ifc /reference m-part.ifc /reference Networking.ifc
The reference options using module-name=filename
would be like this:
cl ... /std:c++latest /reference m=m.ifc /reference M:Part1=m-part.ifc /reference Core.Networking=Networking.ifc
/scanDependencies
(List module dependencies in standard form)
/sourceDependencies:directives
(List module and header unit dependencies)
/headerUnit
(Use header unit IFC)
/exportHeader
(Create header units)