How do I generate trace messages from a header file?

To generate trace messages from source files with file name extensions other than .c, .c++, .cpp, and .cxx, add the -ext parameter to the RUN_WPP macro that invokes the Windows software trace preprocessor.

For example, to generate traces from .c and .h files, use the following statement:

RUN_WPP=$(SOURCES) -km -ext:.c.h

Be sure that the .h files that tracewpp needs to scan are included in $(SOURCES), or add them on the command line.
For example:

RUN_WPP=$(SOURCES) tracedrv.h -km -ext:.c.h

Do not include the .h file that is specified with the -scan: option as a configuration data file, such as trace.h.

The -ext parameter specifies the file types that WPP recognizes as source files. WPP ignores files with a different file name extension. By default, WPP recognizes only .c, .c++, .cpp, and .cxx files.

In versions of Windows prior to Windows Vista because the values of this parameter are case-sensitive, you must list all cases. For example:

RUN_WPP=$(SOURCES) -km -ext:.c.C.h.H

Also, if the header file has the same name as another source file, add the -preserveext parameter to the RUN_WPP macro. For example:

RUN_WPP=$(SOURCES) -km -ext:.c.C.h.H  -preserveext:.c.h

The -preserveext parameter preserves the specified file name extensions when creating the names of trace message header (.tmh) files. This parameter prevents WPP from creating multiple TMH files with the same name. By default, WPP uses only the .tmh file name extension, such as tracedrv.tmh. With the -preserveext parameter, the files are instead named tracedrv.c.tmh and tracedrv.h.tmh.

For a complete list of the optional parameters for RUN_WPP, see WPP Preprocessor.