/Yc   (Create Precompiled Header File)

|  Overview |  How Do I |  Compiler Options

This option instructs the compiler to create a precompiled header (.PCH) file that represents the state of compilation at a certain point. (To find this option in the development environment, click Settings on the Project menu. Then click the C/C++ tab, and click Precompiled Headers in the Category box.)

Command Line	Project Settings	Description
/Yc	Create Precompiled Header File	The compiler compiles all code up to the end of the base source file, or to the point in the base file where #pragma hdrstop occurs.
/Ycfilename	Through Header	The compiler compiles all code up to and including the .H file specified in the Through Header text box (filename).

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 option to specify a name for the precompiled header file.

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

Note   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.

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.

See Also   CreatingPrecompiled Header Files