/Yc (Create Precompiled Header File)

Article
02/20/2018

The latest version of this topic can be found at -Yc (Create Precompiled Header File).

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

Syntax

/Yc[filename]

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 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 option.

If the options /Ycfilename and /Yu (Use Precompiled Header File)filename 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 How to: Open Project Property Pages.
Click the C/C++ folder.
Click the Precompiled Headers property page.
Modify the Create/Use PCH Through File property or the Create/Use Precompiled Header property.

To set this compiler option programmatically

See PrecompiledHeaderThrough and UsePrecompiledHeader.

Example

Consider the following code:

#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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