Creating your own HRESULT?

I already have a project that uses alot of COM, and HRESULTS. ANyways i was wondering if its possible to define your own HRESULT, AND be able to use the FormatMessage() for our own HRESULT?

I dug around and cant find anything. Any ideas?

EDIT

Basically i want to define a set of my own HRESULT's instead of just returning E_FAIL. Or one of the other generic ones. Like E_FAIL is fine. But lets say i want to point out that for example the Geoprocessing subsystem crashed or the file is an invalid Raster Image. The application already uses com through out it.

Yes of course. Typically you create a .mc file and include that in your project. Instruct the mc compiler to build it - this creates a header file and a .rc file. The HRESULTS are defined in the header file. You include the .rc file in your project as normal for the resource compiler to compile - this puts the message definitions into your final module. Then you can use the normal FormatMessage functions to format the messages using the HRESULTS and generate error info and the other stuff.

I have this as the command line for one of my .mc files:

mc   -h "../include" -r "../include" "..\include\errors.mc"

This creates errors.rc and errors.h in the include directory. Then I did:

#include "errors.rc"

in my main .rc file for the project.

The .mc file looks a bit like this:

LanguageNames=(English=0x409:MSG00409)

MessageId=0x1
SymbolicName=SOME_CATEGORY
Language=English
Some Category
.

MessageID=
Severity=Error
SymbolicName=ERROR_INVALID_PROP_INDEX

Language=English
Invalid property index %1
.

with lots of error numbers defined.