Add extern "C" to header process_shims.h #195
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compnerd
reviewed
Oct 4, 2025
| #else | ||
| #define SWIFTSUBPROCESS_EXPORT extern | ||
| #endif | ||
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I wonder if this would be better served with a:
extern "C" {block rather than annotating each of the declarations.
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That's what I originally had, and then I saw #include <Windows.h> and realized I couldn't just wrap the entire thing with extern "C".
... But on second thought, I could just hoist that up to the top, and do the extern "C" thing you suggest (which is a cleaner patch).
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Right, as long as the includes come outside of the block, it is simpler. That also avoids the pitfall of missing the annotation on a future declaration.
Previous, we would encounter missing symbol errors like:
"_subprocess_vm_size()", referenced from:
closure swiftlang#1 () -> Swift.Int in variable initialization expression of Subprocess.(_pageSize in _EDE99368FF43462E0C75AF3C9D4D8F2D) : Swift.Int in AsyncBufferSequence.swift.o
NOTE: found '__subprocess_vm_size' in process_shims.c.o, declaration possibly missing 'extern "C"'
We can reproduce this by running:
xcrun swift build -Xswiftc -cxx-interoperability-mode=default --build-tests
Adding `extern "C"` fixes these issues.
rdar://161624906
iCharlesHu
approved these changes
Oct 4, 2025
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Previous, we would encounter missing symbol errors like:
We can reproduce this by running:
Adding
extern "C"fixes these issues.rdar://161624906