[Mobile] Undefined symbol _registerCustomOps with RapidOCR on iOS/MacCatalyst

[mrsinani]

Describe the issue

When integrating RapidOCR with ONNX Runtime in a .NET MAUI app for iOS and MacCatalyst, I encounter a linker error: Undefined symbols for architecture arm64: _registerCustomOps. The symbol is declared in onnxruntime_c_api.h and expected to be implemented by RapidOCR’s librapidocr.a, which provides custom ops for OCR models. The error occurs during the build for net8.0-ios and net8.0-maccatalyst targets, suggesting that _registerCustomOps is missing from librapidocr.a for arm64 or that ONNX Runtime’s custom ops registration (RegisterCustomOpsUsingFunction) is misconfigured for mobile/mac platforms.

Expected Behavior: The linker should resolve _registerCustomOps, allowing the app to build and run RapidOCR’s ONNX models with custom ops on iOS and MacCatalyst.

Actual Behavior: Linker error: Undefined symbols for architecture arm64: _registerCustomOps.

To reproduce

Load models in .NET MAUI app running on framework net8.0-maccatalyst or ios

Urgency

n/a

Platform

MAUI

OS Version

8.0

ONNX Runtime Installation

Other / Unknown

Compiler Version (if 'Built from Source')

No response

Package Name (if 'Released Package')

None

ONNX Runtime Version or Commit ID

1.13.1

ONNX Runtime API

C++/C

Architecture

ARM64

Execution Provider

Default CPU

Execution Provider Library Version

No response

[github-actions]

This issue has been automatically marked as stale due to inactivity and will be closed in 30 days if no further activity occurs. If further support is needed, please provide an update and/or more details.

[skottmckay]

Reference https://www.nuget.org/packages/Microsoft.ML.OnnxRuntime.Extensions.Dummy to satisfy the symbol.

[jeremy-visionaid]

Also seeing this in 1.22.0

[mrsinani]

i added this to the .csproj file and it works

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