Sign in to follow this  

Unity Never understood Visual studio linker- Error lnk2005.

This topic is 415 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hello,

I build a library which uses other libraries. 

I've encountered a linking error which I could not solve it in a simple manner.

 

I've downloaded TinyObjLoader which is a only header obj loader.

I've put the header in an api source folder which the project configuration references. (Include section)

Then you have to specifcy #define Tinyobject_Implementation to include the implementation in the header only.

The library build and link goes well, the issue is referencing it from another project.

I have a test project which defines a program.cpp (Main here) and it reference a "ClassRenderer.h" which includes my render object, this file includes the "MeshLoader" which includes the TinyObjLoader header.

The output is "ClassRenderer.obj" and "program.obj". (After compilation)

The issue is in the linker, it tries to link program.obj but fails because functions from tinyobjloader are already defined in ClassRenderer.obj.

 

So I solved it by making a new project from the tinyobjloader and creating a static library and removing the #define tinyobject_Implementation preprocessor definition.

Now the test project also links against TinyObjectLoader.lib, which I find unnessecery in a header only library.

How can I solve this without using a .lib or .dll file? 

 

I'm using Visual studio 2013 Community edition.

 

Thanks !

Edited by WoopsASword

Share this post


Link to post
Share on other sites

Then you have to specifcy #define Tinyobject_Implementation to include the implementation in the header only.


To understand the problem, you should read C++ FAQ lite’s “why can’t I separate the definition of my templates class from its declaration and put it inside a .cpp file?”. While not the exact issue described, it provides insight as to what is at play here.

First, the issue is that you apparently didn’t read the readme very thoroughly, as it states you should only define TINYOBJLOADER_IMLEMENTATION for only one translation unit: :^)
 

USAGE
-----
 

#define TINYOBJLOADER_IMPLEMENTATION // define this in only *one* .cc
#include "tiny_obj_loader.h"



Second, the actual issue is that the TINYOBJLOADER_IMPLEMENTATION switches tiny_obj_loader from a symbol importer to symbol exporter. The correct set up should look something like:
// source1.cpp
#define TINYOBJLOADER_IMLEMENTATION
#include <tiny_obj_loader.h>

// source1.cpp will contain all of tiny_obj_loader’s symbols.


// source2.cpp
#include <tiny_obj_loader.h>

// from here, the symbols in tiny_obj_loader contains stubs, which will
// be resolved when the linker links source2.obj with source1.obj

If both source2.cpp and source1.cpp define [tt]TINYOBJLOADER_IMLEMENTATION[/tt], then the linker sees two different sets of identical symbols for tinyobjloader, and that’s an error.

Share this post


Link to post
Share on other sites

 

Then you have to specifcy #define Tinyobject_Implementation to include the implementation in the header only.


To understand the problem, you should read C++ FAQ lite’s “why can’t I separate the definition of my templates class from its declaration and put it inside a .cpp file?”. While not the exact issue described, it provides insight as to what is at play here.

First, the issue is that you apparently didn’t read the readme very thoroughly, as it states you should only define TINYOBJLOADER_IMLEMENTATION for only one translation unit: :^)
 

USAGE
-----
 

#define TINYOBJLOADER_IMPLEMENTATION // define this in only *one* .cc
#include "tiny_obj_loader.h"


Second, the actual issue is that the TINYOBJLOADER_IMPLEMENTATION switches tiny_obj_loader from a symbol importer to symbol exporter. The correct set up should look something like:
// source1.cpp
#define TINYOBJLOADER_IMLEMENTATION
#include <tiny_obj_loader.h>

// source1.cpp will contain all of tiny_obj_loader’s symbols.


// source2.cpp
#include <tiny_obj_loader.h>

// from here, the symbols in tiny_obj_loader contains stubs, which will
// be resolved when the linker links source2.obj with source1.obj

If both source2.cpp and source1.cpp define [tt]TINYOBJLOADER_IMLEMENTATION[/tt], then the linker sees two different sets of identical symbols for tinyobjloader, and that’s an error.

 

 

So if I got it right,

I do not need to specify TINYOBJLOADER_IMLEMENTATION in the library?
Because I use it in only in 1 file (MeshLoader.h) that gets included in couple of files. (And yeah I wrote it inside a single cpp file).

 

It seems weird because I want my library to do all the work so I don't have to specify additional libraries or preprocessor definitions.

 

I've also checked the linked, I was there already and it did not help my case. Neither explains it :|

Edited by WoopsASword

Share this post


Link to post
Share on other sites

This topic is 415 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

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  

  • Forum Statistics

    • Total Topics
      628662
    • Total Posts
      2984095
  • Similar Content

    • By arash khalaqhdoust
      hey guys i hope you doing all well. last night i released my first game in google app store, i really appreciate you guys  to download it. and share your reviews about it
      the idea of game comes from mini hackgame of Bioshock.
       link of download:
      https://play.google.com/store/apps/details?id=com.RVBinary.piperist
      many thanks
    • By ForgedInteractive
      Who We Are
      We are Forged Interactive, a small team of like-minded game developers with the sole purpose of making games we love! Currently, we're progressing very quickly with our first project and there are plenty of opportunities and work for new interested programmers. With this project, our development platform is Unity 5.5.2 and C# as our behavioral language. Since this project is our first release, the game itself is a smaller project though progress is moving quickly. We are looking to finalize the current project and get started on future projects in the near future and are expanding our team to do so.
       
      Who We Are Looking For:
      Programmer Level Designer  
      About the Game
      Ours is the tale of two siblings, thrown into a world of chaos. Living in the shadow of their parents' heroic deeds and their Uncle's colorful military career, Finn and Atia are about to become the next force to shape our world. How will you rise through the ranks of Hereilla and what will be your legacy? Once defeated your enemies turn coat and join you in your adventures. Players can enjoy a range of troops and abilities based on their gameplay style which become more important as maps introduce more challenging terrain, enemies and bosses. Strong orc knights, dangerous shamans, and even a dragon are out on the prowl. Knowing when to fight and when to run, and how to manage your army is essential. Your actions alone decide the fate of this world.
       
      Previous Work by Team
      Although we are working towards our first game as Forged Interactive, our team members themselves have worked on titles including and not limited to:
      Final Fantasy Kingsglaive FIFA 2017 Xcom 2 Civilization  
      What do we expect?
      Reference work or portfolio. Examples what have you already done and what projects you have worked on academic or otherwise. The ability to commit to the project on a regular basis. If you are going on a two-week trip, we don't mind, but it would be good if you could commit 10+ hours to the project each week. Willingness to work with a royalty based compensation model, you will be paid when the game launches. Openness to learning new tools and techniques
       
      What can we offer?
      Continuous support and availability from our side. You have the ability to give design input, and creative say in the development of the game. Shown in credits on websites, in-game and more. Insight and contacts from within the Industry.
       
      Contact
      If you are interested in knowing more or joining, please email or PM us on Skype. A member of our management team will reply to you within 48 hours.
       
      E-mail: Recruitment@ForgedInteractive.com
      Skype: ForgedInteractive
       
      Regards,
      David, Colin and Joseph
       
      Follow us on:
      Facebook: https://www.facebook.com/ForgedInteractive/
      Twitter: @ForgedInteract
      Youtube: https://www.youtube.com/channel/UCpK3zhq5ToOeDpdI0Eik-Ug?view_as=subscriber
      Reddit: www.reddit.com/user/Forged_Interactive

    • By dell96
      I'm trying to make my first project but I'm stuck i don't know how to make my crate to start to spawn again when i hit the start button after i die.
      hoping someone can help!!!
      Crate.cs
      CrateSpawn.cs
      Cratework.cs
      GameController.cs
      GameManager.cs
  • Popular Now