• Advertisement
Sign in to follow this  

Unity Never understood Visual studio linker- Error lnk2005.

This topic is 490 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
Advertisement

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 TINYOBJLOADER_IMLEMENTATION, 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 TINYOBJLOADER_IMLEMENTATION, 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
Sign in to follow this  

  • Advertisement
  • Advertisement
  • Popular Tags

  • Advertisement
  • Popular Now

  • Similar Content

    • By Innoc uous
      If you want to incorporate noise into your shaders, the Turbulance Library has you covered. Using code I gathered from this library, I made a cginc file that contains all you need to easily implement noise into your unity shaders. Who knows how this stuff works, but man, does it work well!
       
      https://pastebin.com/LLCUpJut
       
      Here is an example of what you can create using these noise functions.
       
    • By Nio Martinez
      I'll be buying a new laptop as my workstation for building games, Mostly 3D but not hard core. 
       
      I'm stuck at choosing between these 2 specs below. Does this really matter and if so, can some one tell my how and why it matters. 
      Choice1:
      Intel core i5-8250U (8th gen Kabylake refresh)(6 MB Smart Cache, 1.6 GHz Base with Turbo Boost up to 3.4 GHz) 4 cores 8 threads
      RAM 8 GB DDR4 (2400 MHz)
      GPU 2 GB DDR5 Nvidia MX150 256 bit
      SSD: yes
      Choice2:
      Intel core i7-7500U 2.70GHz Base Processor (4M Cache, up to 3.50 GHz Boost) 2 Cores, 4 Threads
      RAM 4 GB DDR4 (1800 MHz)
      GPU 2 GB DDR5 Nvidia GeForce 940MX 256 bit
      SSD: No
       
    • By Manuel Berger
      Hello fellow devs!
      Once again I started working on an 2D adventure game and right now I'm doing the character-movement/animation. I'm not a big math guy and I was happy about my solution, but soon I realized that it's flawed.
      My player has 5 walking-animations, mirrored for the left side: up, upright, right, downright, down. With the atan2 function I get the angle between player and destination. To get an index from 0 to 4, I divide PI by 5 and see how many times it goes into the player-destination angle.

      In Pseudo-Code:
      angle = atan2(destination.x - player.x, destination.y - player.y) //swapped y and x to get mirrored angle around the y axis
      index = (int) (angle / (PI / 5));
      PlayAnimation(index); //0 = up, 1 = up_right, 2 = right, 3 = down_right, 4 = down

      Besides the fact that when angle is equal to PI it produces an index of 5, this works like a charm. Or at least I thought so at first. When I tested it, I realized that the up and down animation is playing more often than the others, which is pretty logical, since they have double the angle.

      What I'm trying to achieve is something like this, but with equal angles, so that up and down has the same range as all other directions.

      I can't get my head around it. Any suggestions? Is the whole approach doomed?

      Thank you in advance for any input!
       
    • By devbyskc
      Hi Everyone,
      Like most here, I'm a newbie but have been dabbling with game development for a few years. I am currently working full-time overseas and learning the craft in my spare time. It's been a long but highly rewarding adventure. Much of my time has been spent working through tutorials. In all of them, as well as my own attempts at development, I used the audio files supplied by the tutorial author, or obtained from one of the numerous sites online. I am working solo, and will be for a while, so I don't want to get too wrapped up with any one skill set. Regarding audio, the files I've found and used are good for what I was doing at the time. However I would now like to try my hand at customizing the audio more. My game engine of choice is Unity and it has an audio mixer built in that I have experimented with following their tutorials. I have obtained a great book called Game Audio Development with Unity 5.x that I am working through. Half way through the book it introduces using FMOD to supplement the Unity Audio Mixer. Later in the book, the author introduces Reaper (a very popular DAW) as an external program to compose and mix music to be integrated with Unity. I did some research on DAWs and quickly became overwhelmed. Much of what I found was geared toward professional sound engineers and sound designers. I am in no way trying or even thinking about getting to that level. All I want to be able to do is take a music file, and tweak it some to get the sound I want for my game. I've played with Audacity as well, but it didn't seem to fit the bill. So that is why I am looking at a better quality DAW. Since being solo, I am also under a budget contraint. So of all the DAW software out there, I am considering Reaper or Presonus Studio One due to their pricing. My question is, is investing the time to learn about using a DAW to tweak a sound file worth it? Are there any solo developers currently using a DAW as part of their overall workflow? If so, which one? I've also come across Fabric which is a Unity plug-in that enhances the built-in audio mixer. Would that be a better alternative?
      I know this is long, and maybe I haven't communicated well in trying to be brief. But any advice from the gurus/vets would be greatly appreciated. I've leaned so much and had a lot of fun in the process. BTW, I am also a senior citizen (I cut my programming teeth back using punch cards and Structured Basic when it first came out). If anyone needs more clarification of what I am trying to accomplish please let me know.  Thanks in advance for any assistance/advice.
    • By Yosef BenSadon
      Hi , I was considering this start up http://adshir.com/, for investment and i would like a little bit of feedback on what the developers community think about the technology.
      So far what they have is a demo that runs in real time on a Tablet at over 60FPS, it runs locally on the  integrated GPU of the i7 . They have a 20 000 triangles  dinosaur that looks impressive,  better than anything i saw on a mobile device, with reflections and shadows looking very close to what they would look in the real world. They achieved this thanks to a  new algorithm of a rendering technique called Path tracing/Ray tracing, that  is very demanding and so far it is done mostly for static images.
      From what i checked around there is no real option for real time ray tracing (60 FPS on consumer devices). There was imagination technologies that were supposed to release a chip that supports real time ray tracing, but i did not found they had a product in the market or even if the technology is finished as their last demo  i found was with a PC.  The other one is OTOY with their brigade engine that is still not released and if i understand well is more a cloud solution than in hardware solution .
      Would there  be a sizable  interest in the developers community in having such a product as a plug-in for existing game engines?  How important  is Ray tracing to the  future of high end real time graphics?
  • Advertisement