Crash on UE5 Android APK due to missing libc++_shared.so when using third-party native libraries

Development Pipeline & Plugins
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Hello! We are migrating our app from UE4 to UE5 for Android, and during this process, we’ve encountered a crash loop related to some third-party native libraries. These libraries were originally built and packaged in UE4 apk, where they worked as expected by dynamically linking against libc++_shared.so. In UE5, however, the same libraries now fail to load at runtime due to libc++_shared.so no longer being included in the packaged APK by default.

# Crash Log

java.lang.UnsatisfiedLinkError: dlopen failed: library "libc++_shared.so" not found: needed by /lib/arm64/libfoobar.so in namespace classloader-namespaceThis issue did not occur in UE4, as the engine’s main libUE4.so had a dynamic dependency on libc++_shared.so, which was automatically included in the APK, making it also available for our native libraries. In UE5, libUnreal.so is now statically linked with libc++ (as per UE 5.3 release notes), and libc++_shared.so is no longer packaged by default, breaking the native libs dependencies that rely on it.

# Our Attempts & Results

  • Statically link our own libraries with libc++
    • Added -static-libstdc++ to the linker flags.
    • This results in a different crash loop with FMallocBinned2 allocator errors:

Fatal error: [HAL/MallocBinned2.cpp] [Line: 918] FMallocBinned2 Attempt to realloc an unrecognized block+ Likely due to mismatched memory allocators between UE5 and statically linked libc++ code.

  • Add RPATH to system libc++_shared.so path
    • Used linker flags: -Wl,-rpath,/system/lib64 -Wl,-rpath-link,/system/lib64
    • Verified via readelf that RPATH is set, but still get

dlopen failed: library "libc++_shared.so" not found# Temporary Workaround

By forcing the ANSI memory allocator in UE5 and statically linking libc++ in our third-party library builds, we were able to sideload an APK without crash.

# Questions

  1. Is there an officially supported way to integrate third-party dynamic libraries that require libc++_shared.so in UE5?
  2. Can we revert to dynamic libc++ linkage (as in UE4) via some configuration, or must all dependencies migrate to static linkage?

Thanks!

Chun

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Hi Chih-Chun,

You can deploy libc++_shared.so to the APK by adding the following:

[/Script/AndroidRuntimeSettings.AndroidRuntimeSettings] bSkipLibCpp=Falseto your project’s DefaultEngine.ini and allow your third party library to link against it.

Let us know if that resolves the issue and avoids the need to use the ANSI allocator.

Best regards.