• 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
socrates200X

Unity
Defeating SDL linker errors in Visual Studio .NET

8 posts in this topic

I don't know about you guys, but I had a dandy of a time trying to get SDL to work with VS.NET 2003. Even more frustrating was the half-formed answers I found on the GameDev forums, all which went something like:
Quote:
Noob: I'm getting Error A when trying to compile an SDL program in VS.NET. Guru: Change X, fiddle with Y, and copy-and-paste Z. Noob: OK, now I have error B... Guru: Did you fiddle with Y? Noob: Wait, I mysteriously fixed it. Thanks!
Helpful, right? Anyway, in this thread, I plan to methodically go through how to set up SDL properly for VS.NET and go over solutions to the multitude of linker errors that pop up. Hopefully, with a lot of edits, linkage, and feedback, this can be become a stable resource for this prevalent and (I think) not-well-covered problem. Definitions First off, I will be setting up SDL 1.0.8 - Development Runtime with my copy of Visual Studio .NET 2003 - Academic Edition. I will be attempting to get the following piece of code to compile and run, which should display an empty window:
#include "SDL.h"

const int WINDOW_WIDTH = 640;
const int WINDOW_HEIGHT = 480;
const char* WINDOW_TITLE = "SDL Start";

int main(int argc, char **argv)
{
   SDL_Init( SDL_INIT_VIDEO );

   SDL_Surface* screen = SDL_SetVideoMode( WINDOW_WIDTH, WINDOW_HEIGHT, 0, 
      SDL_HWSURFACE | SDL_DOUBLEBUF );
   SDL_WM_SetCaption( WINDOW_TITLE, 0 ); 

   SDL_Event event;
   bool gameRunning = true;

   while (gameRunning)
   {
      if (SDL_PollEvent(&event))
      {
         if (event.type == SDL_QUIT)
         {
            gameRunning = false;
         }
      } 
   }

   SDL_Quit();

   return 0;
}

This code is from Aaron's SDL Tutorial page, which has a lot of helpful SDL info, including a VS.NET setup walkthrough. VS.NET setup Before we delve into any linker errors, let's go over how a simple setup should go:
  1. Open up a new Empty Project (.NET). This should give you (surprise!) an empty project with three folders.
  2. Right-click on the Source Files folder and select Add New Item. Add a .cpp file called main.cpp. Copy-and-paste the above code (or use your own) into main.cpp.
  3. Choose Tools->Options->Projects->VC++ Directories. Under Show Directories For:, choose Include Files, then click the New Line button. Use the Browse (...) button to find your <yourpath>/SDL-1.0.8/include folder. Do the same for your library files by choosing Library Files and <yourpath>/SDL-1.0.8/lib. This ensures that VS.NET can find your SDL files.
  4. Choose Project-><ProjectName> Properties->C/C++ ->Code Generation. For Runtime Library, choose Multi-Threaded Debug DLL (/MDd) if you're running in Debug mode, Multi-Threaded DLL if you're running in Release. This ensures that SDL's dynamic libraries are being loaded correctly.
  5. Choose Project-><ProjectName> Properties->Linker->Input. For Additional Dependencies, type in "sdl.lib sdlmain.lib" (w/o the quotes). This actually links the SDL libraries to your project.
  6. Choose Project-><ProjectName> Properties->Linker->System. For SubSystem, choose Console if your program uses int main(), Windows if it uses WinMain. This ensures that the SDL libraries know which program entry point you'll be using (main vs. WinMain).
  7. Copy SDL.dll from your SDL-1.0.8/lib directory into your project directory.
  8. Build your project. It should compile with perhaps a few warnings, but no errors. Easy, right?
At this point, you probably have more than a few linker errors. The next section goes over these and various home remedies. Linker Errors Fatal error LNK1561: entry point must be defined Causes
  • Properties->Linker->Input->Ignore All Default Libraries is set to Yes
  • Properties->C/C++->Code Generation->Runtime Library is set incorrectly
  • Properties->Linker->System->SubSystem is not set
  • Your main.cpp doesn't contain a main() or WinMain() function.
Explanation Basically, VS.NET is looking to SDL for an entry point, a place to start running the program, and SDL can't find one. This can mean one of two things. There could not be a main()/WinMain() method, in the which case, you should get working on that. Or VS.NET could be reading in the DLL incorrectly. In this case, check that the Runtime Library setting is set for a multi-threaded DLL and matches your build mode (Debug/Release). The linker subsystem can be set to either CONSOLE or WINDOWS. The choice determines whether main() or WinMain() is searched for, so make sure it's set correctly. The whole "Ignore Default Libraries" deal I'm still not sure on, so I won't try to explain it (see LNK4098). Needless to say, setting it to Yes caused a linker error for me, setting it to No did not. Error LNK2019: unresolved external symbol _SDL_main referenced in function _main Causes
  • Your main function signature isn't written exactly like this: "int main(int argc, char **argv)"
Explanation SDL uses type matching to convert the system function call to main() to a call to SDL_main(). Unfortunately, this matcher is very picky, so your main method signature has to be written just so. Using "int main()" or even "int main (int argc, char *argv)" will throw this error. Multiple errors LNK2005: <SomeFunction> already defined in <SomeLibrary>.lib Causes
  • Properties->C/C++->Code Generation->Runtime Library is set incorrectly
Explanation If you don't make sure to specify to VS.NET that SDL is a multi-threaded DLL, it will do some weird things, including redefining a lot of code, causing this particular error. If you're running in Debug, make sure to classify SDL as a Multi-Threaded Debug DLL, and as a Multi-Threaded DLL if you're running in Release. error LNK2019: unresolved external symbol _main referenced in function _mainCRTStartup Causes
  • SDLmain.lib not properly included
Explanation This error is a result of VS.NET not properly finding the SDLmain library file. Either it was never typed into the Linker->Input->Add'l Dependencies field (if not, do that now) or SDLmain.lib isn't where VS.NET is looking for it. Check both that the SDL lib directory is in the VS Library Files directory list and that SDLmain.lib is in that folder. warning LNK4098: defaultlib 'msvcrt.lib' conflicts with use of other libs; use /NODEFAULTLIB:library Causes
  • Properties->Linker->Input->Ignore All Default Libraries is set to No.
Explanation An astute observer will notice that the cause of this warning directly conflicts with the solution to LNK1561. I'm aware of this discrepancy, and am not quite sure how to solve it. Fixing one undoes the other as far my experiments find. The warning doesn't prevent SDL programs from functioning, so I advise leaving it be for now. Links to SDL - VS.NET resources Main SDL page Aaron's SDL Tutorial page Links to other SDL - VS.NET linker error threads SDL error : undefined reference to _alloca_probe more SDL help (trouble with LNK1561, LNK2019, LNK4098) SDL Linker errors (trouble with LNK2019) Linker Error =( (trouble with LNK2019, LNK2005) Got Linker Error (trouble with LNK2019) I'm well aware that this guide is far from complete. I definitely welcome any feedback or clarification on things I missed. As I said, hopefully this will become a resource that will turn an otherwise chipper SDL session into a bitter tug-of-war with the VS.NET linker.
0

Share this post


Link to post
Share on other sites
Good stuff man, but shouldn't this go into SDL/GameDev FAQ, GPwiki.org or sth similiar to them? You know, there are tens of thousands of threads on this forum, and one little thread can be very easily lost. However, putting your efforts in publicly known place will make it easier for people to find and use.

Btw, why are you writing about old SDL version 1.0.8 instead of newest 1.2.9? AFAIK there won't be much difference in terms of compiler/IDE preparations, but at least it won't be confusing begginners.
0

Share this post


Link to post
Share on other sites
Good point. I'll go about transferring this to GPwiki.org. I think the stickied SDL FAQ thread seems more like a set of links than anything else, so I'll link to my new wiki page from there.
0

Share this post


Link to post
Share on other sites
http://sol.gfxile.net/gp/ch01_vc7.html

this link work swell-dandy-fine for me :P

goodluck!
0

Share this post


Link to post
Share on other sites
Just a quick note on the Error LNK2019: unresolved external symbol _SDL_main referenced in function _main problem:

If you let VS 2008 do your work for you, you will get a main that looks like this:

int main(int argc, _TCHAR* argv[])

This won't do. It really has to be:


int main(int argc, char *argv[]) as said above...
0

Share this post


Link to post
Share on other sites
Hi Socrates200X
I was trying the same from yesterday.As you suggested, I changed my linker->System to console nd it solved my problem. Thank you so much , for that detailed post
0

Share this post


Link to post
Share on other sites
Ahhh excellent thank you Socrates (never thought I'd find myself saying that). This:

"The linker subsystem can be set to either CONSOLE or WINDOWS"

...Was the killer for me, as I'd started with an empty project in VS2008 Express. That sorted it!
0

Share this post


Link to post
Share on other sites
Wow....this is an awesome thread...God bless the Socrates200..
I never knew that a tiny difference in my main(..................) would cause these linker errors..

Great work bro !!
1

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

  • Similar Content

    • By KaiZerg
      Dear Colleagues,
      Can you please advise on the issue below:
      I have got several Folders(paper), to keep cheat sheets, practical guides, Lists of sequences ect.
      What is the best way to separate Folders?
      1)
      -Unity all
      -Unreal Engine all
      2)
      -Game art
      -Game Design
      -Game Engine
      -Game Programming
       
    • By suerozcelik
      Hi everyone, My name is Arda Süer, i’m a game developer and producer of Pocket Universe : Create Your Community. Pocket Universe is on pre-order and soon the early access to Steam. I need your help and I want to introduce you to my game. Please read the game story and website content etc. If you have any suggestions tell us and we can develop. Example:"Story is good but you need more faction","You need add bla,bla to the game". Anyway I will put links here to help you to understand Pocket Universe. Story : http://www.pocketuniversegame.com/?page_id=7 Features : http://www.pocketuniversegame.com/?page_id=180 Factions : http://www.pocketuniversegame.com/?page_id=54 Press Release : http://www.pocketuniversegame.com/?page_id=237 If you want to help more, please buy my game Kinguin : https://www.kinguin.net/category/38680/pocket-universe-create-your-community-pre-order-steam-cd-key/ G2A : https://www.g2a.com/pocket-universe-create-your-community-steam-key-global-i10000070716001 Press Relase.rtf
    • By NA-45
      I'm currently working on Metroidvania style game that I was inspired to start by Hollow Knight and Beksiński's art.

       It's built in Unity using C# and has quite a bit done already.  I'm handling the programming myself and have a working model (besides combat which is a WIP) that can be expanded greatly depending on where we decide to take the project.  You can see the current test area here: https://streamable.com/mp5o8  Since I'm not artistically gifted, its all rectangles but can easily be skinned once we've desired on designs.
      I have professional experience using Unity and C# working on both a released game and a prototype as well as having extensive Java knowledge.  I also dabble in Python with a little bit of C++.
      I have worked on and completed many projects before, the most recent being a 2D stick fighting game written ground up in Java Swing (don't ask why): https://www.youtube.com/watch?v=V4Bkoyp_f0o
      I'm looking for a 2D artist (potentially more than one) to create concept and game art and a designer/writer who can help flesh out the story as well as map out and create challenging and eye catching areas.  I can handle most if not all of the programming side of things though if there is anyone who is extremely passionate about this sort of thing, I'd consider splitting the load.
      The end goal is a completed game that can be sold however profit isn't really a concern to me as it's mostly a labor of love from my part.  Any profits would be split between team members however that's pretty far off so don't make that a reason to join.
      ______________________________
      The story I have in mind is something like this:
      A man wakes up in a chasm that stretches seemingly endlessly in both directions lined with enormous statues.

       He discovers a temple with text above a closed gate that tells of the failed kingdom that lies below.  After finding a way around this, he drops down into the subterranean kingdom.  Adventuring through the labrynth below, he comes across different cities in which the residents succumbed to different sins such as Greed, Wrath, etc.  Each city tells a story of how its fixation on something lead to their demise leading up to a fight with the personification of their mistake.
      ______________________________
      An very rough idea for Waterways, a potential area:
       - To enter you must be wearing a pair of glasses that you find somewhere earlier in the ruins.  There are similar glasses found in every home.  Everything appears incredibly beautiful however something seems wrong.  After triggering some event, the glasses break and it's revealed that the glasses are made of some sort of stone that makes everything appear differently.  The city is in ruins and absolutely disgusting as everything was neglected.  
       - The only thing that remains intact is in the center of the city, an incredible statue of a goddess holding up a large sphere of the same material that was used for the glass.  You slowly learn the story behind the statue: the goddess came from the sea that the city lies on and brought prosperity to them.  
       - After opening up the the temple of the goddess that lies right on the edge of the waters, a giant sheet of the glass covers an opening in the back of the temple that reveals the goddess behind it.  You shatter the glass and it becomes apparent that the goddess is actually a disgusting creature half beached and mostly immobile that appears to secrete the material that makes up the glass. Fight ensues.
      ______________________________
      The combat is pretty up in the air and part of the reason I need a designer to bounce ideas off of but I think it will be something like this:
       - 4 orbs equipped at a time
       - 2 orbs selected at a time
       - Pressing the cast button will cast a spell determined by the 2 orbs that are selected
       - Spells cost mana however you can use spells with 0 mana and it will cost health instead
       - These spells in addition to being useful for combat, are the Metroidvania "gating" metchanic.  For instance, one of the conceptualized spells is a water orb + water orb to create a ice pillar that can be either used to block projectiles/enemy paths or to jump on to reach high areas
      ______________________________
      If you're interested or have any questions, contact me through discord.  My id is NA-45#3692. 
       
    • By Qwertyman
      My game (built on the Unity platform, making use of EZ GUI) requires players to log into Facebook. However, when the player is using a language other than English on Facebook, I'm unable to display the localized Username (which is the same as the FB Username) within the game. Any ideas on how this can be tackled?
      PS: Detecting the OS language doesn't really help here because, for all you know, the player might be using one language for the OS, but another one for their Facebook, so.... 
      TIA!
    • By NajeNDa
      Hi there,
      I am a game programmer (C#/C++) who is looking for a project to join. I am computer science engineer plus Master Degree in Game Development, currently working in one the most renown mobile games company (2 years academic experience, 1 year working experience).
      I have developed several prototypes or even games almost ready to release, but I always lack of artists, so I am looking for a project already set up or few artist to begin working in something.
      My preferences are:
      Unity or Unreal Engine 4 based project (UE4 prefered) PC/Console game prefered but mobile is acceptable Not interested in VR Serious team with almost all the roles filled or pretending to be filled 3D project prefered over Sprites Guaranteed 7 work hours per week, Crunch 20 work hours per week  European team (if timezone is not a problem for you, so it is not for me) I am not looking for any kind of money income from games neither the team, I want to do this as a hobby and a way to improve my skills.
      Cheers
  • Popular Now