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macro to disable unused parameters warning?

TreborZehn · 2004-04-12T17:07:18

Hi, I''m programming in Windows and as you may know with WinMain function is required to take a specific set of parameters and a couple of them are rarely used. The problem is I get a "unused parameters warning" whenever I compile my code. I''m a bit of a purist when it comes to warnings. I never disable them with a compiler switch because there have been many times when they''ve helped me catch bugs, and write cleaner/more efficient code. Therefore I don''t want to disable the "unused parameters" warning all together. Is there a macro I can use (ANSI C would be best but even something included via "windows.h" would be OK) that I can wrap around parameter names that I don''t want to be warned about. For example... int MyFunc(int param1, int param2) { TOUCH_PARAMETER(param2); return (param1 + 1); } Any advice would be appreciated. Thanks "Good code will come and go, but bad code sticks around."

General and Gameplay Programming Programming

Started by TreborZehn April 12, 2004 10:04 AM

13 comments, last by TreborZehn 20 years ago

Anonymous

April 12, 2004 11:25 AM

quote:Original post by TreborZehn
It''s also interesting to me that leaving a parameter unnamed doesn''t give the warning... not sure if I like that idea. I mean I''m not doubting that it works I''m just thinking if it''s a good thing from a Programming Practices perspecitive.

Suppose you''re implementing an interface defined by someone else. Then you might not want to utilize all parameters you get in a function call (while somone else, in another implementation of the same interface, could need all parameters). Therefore it''s really necessary not being forced to use all parameters, and it''s a really valid and useful thing to do. So not having a warning in that case is a good thing.

A static code analyzer, such as LINT, can probably be configured to issue warnings in this case.

BriTeg

168

April 12, 2004 12:02 PM

quote:Original post by TreborZehn
It''s also interesting to me that leaving a parameter unnamed doesn''t give the warning... not sure if I like that idea.

Fior MSVC compilers, the default warning level is 3, which doesn''t included warnings about unreferenced parameters and a whole whack of other minor things. I always turn my warning level up to 4 (the highest). Well, that''s not exactly true I guess: sometimes certain 3rd party API''s spew mountains of warnings on level 4, so then I revert back to level 3.

Brianmiserere nostri Domine miserere nostri

seanw

254

April 12, 2004 12:32 PM

quote:Original post by BriTeg
Fior MSVC compilers, the default warning level is 3, which doesn''t included warnings about unreferenced parameters and a whole whack of other minor things. I always turn my warning level up to 4 (the highest). Well, that''s not exactly true I guess: sometimes certain 3rd party API''s spew mountains of warnings on level 4, so then I revert back to level 3.

I like to keep the warning level high too, just to stop obscure bugs creeping in. Most compilers have options to set the warning level to be less strict for different files (ie you can set MSVC to less strict warnings only for the 3rd party API''s that have warnings).

Aprosenf

372

April 12, 2004 04:34 PM

In case you''re wondering, there''s no "magic" behind the UNREFERENCED_PARAMETER macro. Here''s the defintion from winnt.h (which gets included via windows.h, so you don''t need to add any extra includes):

#if ! (defined(lint) || defined(_lint))#define UNREFERENCED_PARAMETER(P)          (P)#define DBG_UNREFERENCED_PARAMETER(P)      (P)#define DBG_UNREFERENCED_LOCAL_VARIABLE(V) (V)#else // lint or _lint// Note: lint -e530 says don''t complain about uninitialized variables for// this.  line +e530 turns that checking back on.  Error 527 has to do with// unreachable code.#define UNREFERENCED_PARAMETER(P)          \    /*lint -e527 -e530 */ \    { \        (P) = (P); \    } \    /*lint +e527 +e530 */#define DBG_UNREFERENCED_PARAMETER(P)      \    /*lint -e527 -e530 */ \    { \        (P) = (P); \    } \    /*lint +e527 +e530 */#define DBG_UNREFERENCED_LOCAL_VARIABLE(V) \    /*lint -e527 -e530 */ \    { \        (V) = (V); \    } \    /*lint +e527 +e530 */#endif // lint or _lint

So basically, it''s just doing an assignment statement which the compiler should optimize away.

bytecoder

100

April 12, 2004 05:07 PM

quote:
In case you''re wondering, there''s no "magic" behind the UNREFERENCED_PARAMETER macro. Here''s the defintion from winnt.h (which gets included via windows.h, so you don''t need to add any extra includes):

...

So basically, it''s just doing an assignment statement which the compiler should optimize away.

Wow, that''s odd; I thought the macro would be defined more like this:

#define UNREFERENCED_PARAMETER(p) /*does nothing*/

I usually just leave out the name if I don''t use it.

macro to disable unused parameters warning?

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