/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.
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
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.