target_link_libraries

[davegullo]

✍🏼 Dear Diary,
I ran into this problem when trying to build obs-moq where libmoq was not ending up in the final obs-moq.so file in Linux. Changing this CMakeLists.txt setting did the trick.

Problem:

When building projects that link against libmoq (like obs-moq), the Rust static library was not being properly linked into the final binary. This resulted in:
Dramatically smaller output files (~310KB instead of ~31MB)
Runtime errors: undefined symbol: moq_origin_consume and other moq API functions

Root Cause:

The original code used:
target_link_options(moq INTERFACE "$<LINK_ONLY:${RUST_LIB}>")

This approach has issues:
target_link_options is not designed for libraries - it's meant for linker flags (like -Wl,--as-needed), not library files
The $<LINK_ONLY:...> generator expression doesn't reliably work with INTERFACE targets in all CMake configurations
CMake's dependency tracking doesn't properly recognize the static library as a link dependency, so it may be silently omitted during the link phase

Solution:

Using target_link_libraries is the canonical CMake approach for linking libraries:
target_link_libraries(moq INTERFACE "${RUST_LIB}")

[coderabbitai]

Walkthrough

The change modifies the CMake build configuration for the moq target in rs/libmoq/CMakeLists.txt. Specifically, it replaces target_link_options with target_link_libraries to link the Rust library. This substitution changes how the linker processes the dependency—instead of applying it as a direct linker option, it creates an explicit target dependency. As a result, the Rust library will appear after object files in the link command sequence rather than being forced at a specific position. Explanatory comments were added to document this change.

Pre-merge checks and finishing touches

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The title 'target_link_libraries' is too vague and does not clearly convey the main purpose of the change, which is fixing linker errors to include libmoq in final output.	Use a more descriptive title that explains the problem being solved, such as 'Fix libmoq linking to prevent undefined symbol errors' or 'Replace target_link_options with target_link_libraries to properly link libmoq'.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description clearly explains the problem (libmoq not being linked), root cause (misuse of target_link_options), and solution (switching to target_link_libraries), demonstrating strong alignment with the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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• rs/libmoq/CMakeLists.txt

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🔇 Additional comments (1)

rs/libmoq/CMakeLists.txt (1)

51-53: Excellent fix for the linker issue!

The change from target_link_options to target_link_libraries is the correct approach. target_link_libraries properly establishes the library dependency and ensures CMake tracks the static library correctly in the link command. The added comments clearly explain the rationale.

The removal of the $<LINK_ONLY:...> generator expression is also appropriate here—for an INTERFACE target, you want the library to propagate to consumers.

Please confirm that this change resolves the original obs-moq build issue on Linux (where binaries were missing the ~31MB Rust library and producing undefined symbol errors).

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_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[kixelated]

idk I don't pretend to understand Cmake.