Hi All,
Unreal Engine Version: 5.6.1
IDE: Rider 2025.2.3
Visual Studio 2022
Just started working with UE5 and trying to compile with C++. I am struggling to get Live coding to work in UE5, it gives me the below error. ULANG_PLATFORM must be defined and I am not sure how I do that.
Error Line: C:\Program Files\Epic Games\UE_5.6\Engine\Source\Runtime\Solaris\uLangCore\Public\uLang\Common\Common.h(13,1): fatal error C1189: #error: ULANG_PLATFORM must be defined.
error ULANG_PLATFORM must be defined.
Log Contents:
Manual recompile triggered
---------- Creating patch ----------
Running C:\Program Files\Epic Games\UE_5.6\Engine\Build\BatchFiles\Build.bat -Target=“SlashEditor Win64 Development -Project=”“C:/Users/steve/Documents/Unreal Projects/C++ Ultimate Game Developer/Slash/Slash.uproject”“” -LiveCoding -LiveCodingModules=“C:/Program Files/Epic Games/UE_5.6/Engine/Intermediate/LiveCodingModules.json” -LiveCodingManifest=“C:/Program Files/Epic Games/UE_5.6/Engine/Intermediate/LiveCoding.json” -WaitMutex -LiveCodingLimit=100
Using bundled DotNet SDK version: 8.0.300 win-x64
Running UnrealBuildTool: dotnet “…\Engine\Binaries\DotNET\UnrealBuildTool\UnrealBuildTool.dll” -Target=“SlashEditor Win64 Development -Project=”“C:/Users/steve/Documents/Unreal Projects/C++ Ultimate Game Developer/Slash/Slash.uproject”“” -LiveCoding -LiveCodingModules=“C:/Program Files/Epic Games/UE_5.6/Engine/Intermediate/LiveCodingModules.json” -LiveCodingManifest=“C:/Program Files/Epic Games/UE_5.6/Engine/Intermediate/LiveCoding.json” -WaitMutex -LiveCodingLimit=100
Log file: C:\Users\steve\AppData\Local\UnrealBuildTool\Log.txt
Building SlashEditor…
Using Visual Studio 2022 14.38.33145 toolchain (C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130) and Windows 10.0.26100.0 SDK (C:\Program Files (x86)\Windows Kits\10).
Determining max actions to execute in parallel (24 physical cores, 24 logical cores)
Executing up to 24 processes, one per physical core
Using Unreal Build Accelerator local executor to run 5 action(s)
Storage capacity 40Gb
---- Starting trace: 251013_135129 ----
UbaSessionServer - Disable remote execution (remote sessions will finish current processes)
------ Building 5 action(s) started ------
[1/5] Compile [x64] SharedPCH.UnrealEd.Project.ValApi.ValExpApi.Cpp20.cpp
[2/5] Compile [x64] Item.cpp
C:\Program Files\Epic Games\UE_5.6\Engine\Source\Runtime\Solaris\uLangCore\Public\uLang\Common\Common.h(13,1): fatal error C1189: #error: ULANG_PLATFORM must be defined.
error ULANG_PLATFORM must be defined.
^
[3/5] Compile [x64] Slash.cpp
[4/5] Compile [x64] PerModuleInline.gen.cpp
[5/5] Compile [x64] Module.Slash.gen.cpp
Trace written to file C:/Users/steve/AppData/Local/UnrealBuildTool/Log.uba with size 5.5kb
Total time in Unreal Build Accelerator local executor: 28.04 seconds
Result: Failed (OtherCompilationError)
Total execution time: 28.53 seconds
Build failed.