[docs] Improve docs on EH-SjLj interaction #26187
Merged
+16
−5
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This was written several years ago, and now you don't need to pass `-sSUPPORT_LONGJMP=wasm` explicitly when you use `-fwasm-exceptions`. The kind of SjLj support will be determined by the kind of EH support. But you need a caution when you link C and C++ code together, as noted in emscripten-core#26165.
dschuff
reviewed
Jan 29, 2026
| explicitly. | ||
|
|
||
| To use the WebAssembly EH and setjmp-longjmp support together: | ||
| But you need to pass ``-sSUPPORT_LONGJMP=wasm`` explicitly when you link C and |
Member
There was a problem hiding this comment.
This flag is to be used at compile time?
What's the generated code in an object file with SUPPORT_LONGJMP=emscripten?
Member
Author
There was a problem hiding this comment.
I clarified the sentence so that it means compile time.
If it's not LTO, the flag you give -sSUPPORT_LONGJMP= determines the kind of SjLj transformation. In LTO, it decides whether +exception-handling will be included in target-features function attribute (which was the reason for #26165)
dschuff
approved these changes
Jan 29, 2026
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This was written several years ago, and now you don't need to pass
-sSUPPORT_LONGJMP=wasmexplicitly when you use-fwasm-exceptions. The kind of SjLj support will be determined by the kind of EH support.But you need a caution when you link C and C++ code together, as noted in #26165.