Stream: git-wasmtime

Topic: wasmtime / issue #7592 who is supposed to call `_initiali...

Wasmtime GitHub notifications bot (Nov 28 2023 at 06:14):

yamt opened issue #7592:

i have a preview1 reactor module, which exports _initialize.
when adapting it with wasi_snapshot_preview1.reactor.wasm and loading the resulted component with wasmtime,
i expected the _initialize export of the original module is somehow called during the component startup.
however, it doesn't seem to be called.

Wasmtime GitHub notifications bot (Nov 28 2023 at 15:08):

alexcrichton commented on issue #7592:

Currently the *.reactor.wasm adapter doesn't do anything with _initialize, so you'll likely want to build your own adapter which calls it as part of the start function or implicitly as part of exports.

Alternatively a convention could be built into wit-component to perhaps do this automatically but that would be pretty complicated implementation-wise since it would need to handle the fact that _initialize is optional.

Wasmtime GitHub notifications bot (Nov 29 2023 at 03:12):

yamt commented on issue #7592:

Currently the *.reactor.wasm adapter doesn't do anything with _initialize, so you'll likely want to build your own adapter which calls it as part of the start function or implicitly as part of exports.

ok.
i put a hack in the (non-standard) entry point of my module and it's working well.

Alternatively a convention could be built into wit-component to perhaps do this automatically but that would be pretty complicated implementation-wise since it would need to handle the fact that _initialize is optional.

i guess it's necessary for a reactor built with wasi-libc to work correctly.

Wasmtime GitHub notifications bot (Nov 29 2023 at 16:28):

alexcrichton commented on issue #7592:

Most of the usage of _initialize in wasi-libc for example has been pushed to lazy instead of eager initialization, which if possible is what I would recommend for other uses as well. Otherwise feel free to open an issue on the wasm-tools repository for a proposal about how to add _initialize support to wit-component and adapters of course!

Wasmtime GitHub notifications bot (Jul 28 2025 at 20:45):

alexcrichton closed issue #7592:

i have a preview1 reactor module, which exports _initialize.
when adapting it with wasi_snapshot_preview1.reactor.wasm and loading the resulted component with wasmtime,
i expected the _initialize export of the original module is somehow called during the component startup.
however, it doesn't seem to be called.

Wasmtime GitHub notifications bot (Jul 28 2025 at 20:45):

alexcrichton commented on issue #7592:

I believe this is now handled, so closing.

Last updated: Dec 13 2025 at 19:03 UTC