MIDL and Enum Name-Mangling

I've gotten obscure build errors when building our SFP stuff with a bunch of dependent IDL (MIDL) files that contain ENUMs. A "deja" search finally set me straight - figured out how to avoid this name mangling issue...

We start with something like this in IDL:

typedef enum

{

	SFP_STATE_IDLE	=	0x00000000,

	SFP_STATE_UPDATECHECK_BUSY =	0x00000001,

	SFP_STATE_INSTALL_BUSY	=	0x00000002	

}	SFP_STATE;

Then a method somewhere that uses this enum:
HRESULT State([out, retval] SFP_STATE *pVal);

The Problem
When calling code uses #import on this generated type library, you end up with something like this in the .TLH file:

typedef enum __MIDL___MIDL_itf_UpdateAdvisor_0257_0003 SFP_STATE;

enum __MIDL___MIDL_itf_UpdateAdvisor_0257_0003;

   ... 

   ... 

enum __MIDL___MIDL_itf_UpdateAdvisor_0257_0003

{

    SFP_STATE_IDLE = 0,

    SFP_STATE_UPDATECHECK_BUSY = 1,

    SFP_STATE_INSTALL_BUSY = 2

};

If you use this #import statement in more than one client file/project, you may get multiply defined symbols. The trick to getting around this is to use the "exclude" modifier on the #import in subsequent files/projects. The problem I've had is what to exclude. The multiply defined symbol is really this enum with a big mangled name.

You can exclude by referring to this mangled name:
exclude( "__MIDL___MIDL_itf_vzInstall_0263_0003"),
but this is not optimal. You see, this symbol is *sometimes* mangled to slightly different numeric codes on different machines! I haven't pinpointed where the generated number comes from, especially the 0263 portion (the part that changes on various machines) in the above name. At work here, almost all machines come up with 0263, but then on a new laptop with a fresh install of the VS tools, it generates as 0264. So....how to avoid this constant chase of the mangled names...

The Solution
Thanks to this thread (search google with "#import" enum generated group:microsoft.public.* if the link doesn't work), I found a slightly different way to define the enums in IDL, to avoid the mangling all together.

typedef [public] enum eSfpState

{

	SFP_STATE_IDLE		=	0x00000000,

	SFP_STATE_UPDATECHECK_BUSY	=	0x00000001,

	SFP_STATE_INSTALL_BUSY		=	0x00000002	

}	SFP_STATE;

Notice the [public] enum eSfpState difference from the original way of describing.

This results in the .tlh having a nicer set of #defines:

typedef enum eSfpState SFP_STATE;

enum eSfpState;

   ... 

   ...

enum eSfpState

{

    SFP_STATE_IDLE = 0,

    SFP_STATE_UPDATECHECK_BUSY = 1,

    SFP_STATE_INSTALL_BUSY = 2

};

Now you leave the method signature the same in IDL:
HRESULT State([out, retval] SFP_STATE *pVal);
And the caller still uses SFP_STATE as the enum parameter type, and all is well in the world !!!

Wahoo!!



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Netflix for Video Games

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$22/mo
Gamefly.com

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SourceForge.net:
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As seen on The Screen Savers:
SourceForge.net: Project Info - TightVNC Remote control to Windows and Linux.
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National Do Not Call Registry

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Just so I remember, registered using standard yahoo email address. (Home phone and 2 cell phones)

Register here

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Apparently, Adelphia is starting to rollout HiDef tv to select markets. Damnit -- not in Carlsbad yet!? ;-(

Questions:

• what hardware to decode HD?
  
• what channels?
  
• cost?
  

keywords: HD HiDef High Definition HDTV

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ATL headers with DDK are not mainstream. MS recommends only using them if you are doing driver development.

We found some differences in the handling of CSimpleArray -- uses address-of operator & when doing Add on array. When storing COM smart pointers in the array, address-of operator calls Release( ) on the pointer first -- NOT GOOD.

DDK docs that describe the ATL headers here

excerpt here:

---

Included ATL Headers
The version of ATL that ships with this Windows 2000 DDK is not the same as the Visual C++ version and should only be used for driver development. General purpose ATL source code is available with your normal Visual C++ installation.

---

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Activate NetMeeting in Windows XP
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Start, Run, "conf". walk through wizard steps and it will be there

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Hacking - Tehnically Speaking. Guest on The Screen Savers. His web site here.
Ejovi Nuwere

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Get Started with Digital Photography
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set user rights from a remote machine

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Spot on The Screen Savers about packet sniffing. Kevin Rose shows the tool called Iris. Not only a packet sniffer, but recreates the packets and shows you the native application (web browser, even Outlook email!).

Bummer, it's apparently $1000, but there's a 15 day trial.

Some suggestions to protect against this sniffing:
- Trillian Pro, offers encryption
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Wireless Links

NetStumbler
Access Point coverage, and a whole lot more...

War Driving
driving around the city, looking for access points! :)

Encryption Key Recovery Tool (Really, a way to hack the WEP encryption key?)

keywords: wireless, acess point, dlink, wardriving, war driving


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Time Warner Cable - PVR documents

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The Screen Savers - Hacking and Tracking

ASTALAVISTA SECURITY GROUP Kevin Rose (The Screen Savers hacker) recommended this site for all underground searching.

Yoshi's list of mod sites:

• [H]ard|Forum - forum for hardware and modding advice from experts
  
• VHForums.net - tag line says it all: "Where the Mawd Gawds Hang Out!"
  
• Pheaton Forums - Yet another great bulletin for modders, by modders
  
• Overclockers.com - Anyone looking to overclock their CPU should visit this site
  
• Electronics Information Online (EIO) - Once you figure out what you need, this is the place to find great deals on hardware
  

Sarah Lane -- NeoTrace, a tool to track back to an ISP for a given poster, user, etc.


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MPEG-4: Movie Encoding Guide Be sure to go down to the bottom and select other parts of the Table of Contents. There are a lot of good articles here...

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Microsoft Baseline Security Analyzer
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ActiveState has an install for this here.
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