/Yc (Create Precompiled Header File)

Article
08/03/2021

Instructs the compiler to create a precompiled header (.pch) file that represents the state of compilation at a certain point.

Syntax

/Yc
/Ycfilename

Arguments

filename
Specifies a header (.h) file. When this argument is used, the compiler compiles all code up to and including the .h file.

Remarks

When /Yc is specified without an argument, the compiler compiles all code up to the end of the base source file, or to the point in the base file where a hdrstop directive occurs. The resulting .pch file has the same base name as your base source file unless you specify a different file name using the hdrstop pragma or the /Fp option.

The precompiled code is saved in a file with a name created from the base name of the file specified with the /Yc option and a .pch extension. You can also use the /Fp (Name .Pch File) option to specify a name for the precompiled header file.

If you use /Ycfilename, the compiler compiles all code up to and including the specified file for subsequent use with the /Yu (Use Precompiled Header File) option.

If the options /Ycfilename and /Yufilename occur on the same command line and both reference, or imply, the same file name, /Ycfilename takes precedence. This feature simplifies the writing of makefiles.

For more information on precompiled headers, see:

To set this compiler option in the Visual Studio development environment

Select a .cpp file. The .cpp file must #include the .h file that contains precompiled header information. The project's /Yc setting can be overridden at the file level.
Open the project's Property Pages dialog box. For details, see Set C++ compiler and build properties in Visual Studio.
Open the Configuration Properties, C/C++, Precompiled Headers property page.
Modify the Precompiled Header property.
To set the filename, modify the Precompiled Header File property.

To set this compiler option programmatically

See PrecompiledHeaderThrough and UsePrecompiledHeader.

Example

Consider the following code:

// prog.cpp
// compile with: cl /c /Ycmyapp.h prog.cpp
#include <afxwin.h>   // Include header for class library
#include "resource.h" // Include resource definitions
#include "myapp.h"    // Include information specific to this app
// ...

When this code is compiled with the command CL /YcMYAPP.H PROG.CPP, the compiler saves all the preprocessing for AFXWIN.h, RESOURCE.h, and MYAPP.h in a precompiled header file called MYAPP.pch.

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