• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
Sunsharior

Is this commenting macro safe to use?

9 posts in this topic

Hello everyone.

 

I'm using a simple macro to comment out part of my code in release build, but i'm wondering if this could lead to some sort of problem, as i'm trying to cheat the precompiller into adding comments against the rule.

 

I use this to avoid writing duplicated code.

 

Basically, here is the macro

#if defined DEBUG
#define MACRO 
#else
#define MACRO );/ ## /
#endif

What it does is: If i'm in debug build, it does nothing. If i'm in release build, it close a function and comment the rest of the line.

The "/ ## /" part is needed to trick the compiler into thinking comment dont exist. But they do.

 

This is how i use the macro. (The code is simplified)

//Initialize a long list of interfaced classes into a map, allowing easy Factory access.
void Bar()
{
    //Assume each different letters is an interfaced class
    Foo(A0, A1 MACRO, A2, A3, A4);
    Foo(B0, B1 MACRO, B2, B3, B4);
    // Many Foo later...
    Foo(Z0, Z1 MACRO, Z2, Z3, Z4);
}

#if defined DEBUG
//Types don't really matter. Just the number of parameters is interesting.
void Foo(Type0, Type1, Type2, Type3, Type4)
{
    // Do something, in debug
}
#else
void Foo(Type0, Type1)
{
    // Do something, in release
}
#endif



As you can see, in release build, the compiler will see "Foo(A0, A1 );" as the comment will clear the rest of the line.
This way, i avoid writing this code:

#if defined DEBUG
Foo(A0, A1, A2, A3, A4);
Foo(B0, B1, B2, B3, B4);
// Many Foo later...
Foo(Z0, Z1, Z2, Z3, Z4);
#else
Foo(A0, A1);
Foo(B0, B1);
// Many Foo later...
Foo(Z0, Z1);
#endif

The reason i use it is to avoir writing duplicate code to avoid possible Copy/Paste errors.

As of writing this post, the macro work fine in either build, but i have this strange feeling i'm doing something cringe-worthy.

 

Am i really going overboard just to avoid writing duplicated code?

If so, is there other options?

Edited by Sunsharior
0

Share this post


Link to post
Share on other sites

I must have some gaps in my knowledge, as i thought comments are removed before the precompiler processes the macros?

I know a macro like this wont work, because the compiler will see the two slashes as a comment and remove/ignore them:

#define MACRO //

 

But why/how does the one in the OP work?

#define MACRO / ## /

0

Share this post


Link to post
Share on other sites


## takes two characters and combine them. It takes / and / and turns it into //.

Also known as token concatenation.

0

Share this post


Link to post
Share on other sites

 

But why/how does the one in the OP work?

#define MACRO / ## /

This uses the concatenation operator "##" to insert a comment "//"

Edit: beaten by servant of the lord.

Edited by Sunsharior
0

Share this post


Link to post
Share on other sites

Keep in mind that using token pasting to synthesize a comment is not actually allowed by the standard, as it explicitly states comment removal occurs before macro processing - many compilers do it after, or both before and after, but some (like gcc) will outright reject the macro as it would expand to an illegal token after the macro processing phase:

error: pasting "/" and "/" does not give a valid preprocessing token

I would be very wary of using that macro on an unknown compiler, there is no telling what it would actually do.

2

Share this post


Link to post
Share on other sites

As many already stated, i will revise the logic of my code to avoid using preprossesor-comments altogether. I already have an idea on how i might do that cleanly.

I understand now, the macro is not standard and should be avoided.

 

Thank you everyone.

0

Share this post


Link to post
Share on other sites

Yes, i do realize token pasting is occuring, the question was more in line with "why are comments allowed to exist after the macro processing", since afaik they are removed before it.

Bacterius' answer is what i was after, thanks!

0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0