CODEWITHSUNDEEP
c++opensslunreal-engine4
Vincent Guillon
Vincent Guillon

Reputation: 21

UE4 packaging error : linking problems with OpenSSL

I'm currently trying to make a project with Unreal Engine 4, that executes HTTPS requests from C++ code.

In order to achieve that goal, I'm using the library c++-httplib, which requires OpenSSL, so I added it to my project, giving the location of include and lib files within my Project.Build.cs file, especially libssl.lib et libcrypto.lib.

Everything works perfectly fine within the Editor, but as soon as I try to package my project, I get the following errors (line 11-12)

1:UEBuildTarget.GenerateManifest: Writing manifest to C:\MyProject\Intermediate\Build\Manifest.xml
2:ActionGraph.IsActionOutdated: MyProject.exe: Produced item "MyProject.exe" doesn't exist.
3:ActionGraph.DeleteOutdatedProducedItems: Deleting outdated item: C:\MyProject\Binaries\Win64\MyProject.pdb
4:UEBuildTarget.TryRecycleVersionManifests: Target is not using a version file.
5:ParallelExecutor.ExecuteActions: Building 1 action with 12 processes...
6:ParallelExecutor.ExecuteActions:   [1/1] MyProject.exe
7:ParallelExecutor.ExecuteActions:   vpxmd.lib(vpx_src_vpx_codec.obj) : .netmodule ou module MSIL compil� avec /GL trouv�; red�marrage de l'�dition de liens avec /LTCG�; ajoutez /LTCG � la ligne de commande de l'�dition de liens pour am�liorer les performances de l'�diteur de liens
8:ParallelExecutor.ExecuteActions:      Cr�ation de la biblioth�que C:\MyProject\Binaries\Win64\MyProject.lib et de l'objet C:\MyProject\Binaries\Win64\MyProject.exp
9:ParallelExecutor.ExecuteActions:   G�n�ration de code en cours
10:ParallelExecutor.ExecuteActions:   Fin de la g�n�ration du code
11:ParallelExecutor.ExecuteActions:   libcurl_a.lib(pem_all.obj) : error LNK2005: PEM_read_bio_RSAPrivateKey d�j� d�fini(e) dans libcrypto64MD.lib(libcrypto-1_1-x64.dll)
12:ParallelExecutor.ExecuteActions:   libcurl_a.lib(pem_pkey.obj) : error LNK2005: PEM_read_bio_PrivateKey d�j� d�fini(e) dans libcrypto64MD.lib(libcrypto-1_1-x64.dll)
13:ParallelExecutor.ExecuteActions:   C:\MyProject\Binaries\Win64\MyProject.exe : fatal error LNK1169: un ou plusieurs symboles d�finis � diff�rentes reprises ont �t� rencontr�s
14:Log.WriteException: ==============================================================================
15:Log.WriteException: ERROR: UBT ERROR: Failed to produce item: C:\MyProject\Binaries\Win64\MyProject.exe
16:Log.WriteException:        (see C:\Users\etudiant\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_4.21\UBT-MyProject-Win64-Development.txt for full exception trace)
17:Log.WriteException: 
18:Log.WriteException: BuildException: UBT ERROR: Failed to produce item: C:\MyProject\Binaries\Win64\MyProject.exe
19:Log.WriteException:    à UnrealBuildTool.ActionGraph.ExecuteActions(BuildConfiguration BuildConfiguration, List`1 ActionsToExecute, String& ExecutorName, String TargetInfoForTelemetry, EHotReload HotReload) dans D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\System\ActionGraph.cs:ligne 507
20:Log.WriteException:    à UnrealBuildTool.UnrealBuildTool.RunUBT(BuildConfiguration BuildConfiguration, String[] Arguments, FileReference ProjectFile, Boolean bCatchExceptions) dans D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\UnrealBuildTool.cs:ligne 1699
21:Log.WriteException: ==============================================================================
22:UnrealBuildTool.RunUBT: Total build time: 42,37 seconds (Parallel executor: 0,00 seconds)

And I don't have a clue of what I can do about it.

Upvotes: 2

Views: 1843

Answers (1)

Shane Powell
Shane Powell

Reputation: 14158

The main problem is linker error LNK2005 which means you are linking in the same symbol (code) from two different places.

Namely "PEM_read_bio_RSAPrivateKey" and "PEM_read_bio_PrivateKey" from "libcurl_a.lib" and "libcrypto64MD.lib".

At a guess the "libcurl_a" library has openssl statically linked in already and you are trying to linked in the the openssl dynamic library "libcrypto64MD" (libcrypto-1_1-x64.dll).

You may be able to drop the linking in of "libcrypto64MD.lib" and get open ssl from "libcurl_a.lib". If you can't because of missing symbols, you may need to compile or get a different version of libcurl that uses the dll version of the openssl library.

Upvotes: 1

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