PS: the .js file generated by emcc has functions like this:
/** @type {function(...*):?} */
function _sapp_js_add_beforeunload_listener(
) {
err('missing function: sapp_js_add_beforeunload_listener'); abort(-1);
}
(...ok, so that's where the JS console error is coming from...)
On Saturday, 29 January 2022 at 18:12:42 UTC+1 Floh wrote:
> I'm currently tinkering with bringing one of my toy Zig projects to the
> web via
> Alon's nice gist here which uses emcc only for the linker step:
>
> https://gist.github.com/kripken/58c0e640227fe5bac9e7b30100a2a1d3
>
> ...and it *nearly* works except for code that uses EM_JS() macros.
>
> The project (https://github.com/floooh/pacman.zig) consists of some C
> code (my cross-platform 'sokol headers') which uses EM_JS() quite
> extensively (very handy for STB-style single-file libraries), and at the
> top, the "game code" is written in Zig.
>
> I'm compiling all code with Zig with the wasm32-wasi target
> (wasm32-emscripten exists, but currently doesn't seem to be supported by
> the Zig compiler), and then use emcc for linking.
>
> Long story short, it works except for the one problem that emcc cannot
> resolve any functions which have been defined with EM_JS(). If I compile
> the same library with emcc instead of Zig it works.
>
> So my question is: does emcc also do some "EM_JS() magic" when compiling
> the source code which contains EM_JS macros? Maybe I'm missing some Clang
> command line options which emcc inserts?
>
> The errors look like this:
>
> error: undefined symbol: sapp_js_add_clipboard_listener (referenced by
> top-level compiled C/C++ code)
>
> Followed by:
>
> warning: _sapp_js_add_clipboard_listener may need to be added to
> EXPORTED_FUNCTIONS if it arrives from a system library
> ...there's also a single warning about malloc:
>
> ...if I compile with "-s ERROR_ON_UNDEFINED_SYMBOLS=0", then the code
> breaks at runtime failing to resolve those EM_JS() functions, e.g.:
>
> "missing function: sapp_js_pointer_init"
>
> Compiling the same static link library with emcc, it magically works.
>
> If I look at both libraries with nm I don't see much of a difference, e.g.
> here's the relevant parts from the emcc-compiled library, every EM_JS
> symbol has an "D __em_js..." entry, and a matching "U sapp_js..." entry,
> e.g.:
>
> 0000185f D __em_js__sapp_js_add_beforeunload_listener
> ...
> U sapp_js_add_beforeunload_listener
> ...
>
> The Zig-compiled library has the same entries:
>
> 00001841 D __em_js__sapp_js_add_beforeunload_listener
> ...
> U sapp_js_add_beforeunload_listener
> ...
>
> ...yet one library (the zig-compiled) produces linker errors for those
> symbols, and the other (emcc-compiled) works.
>
> Clearly I'm missing something. I was expecting that all the EM_JS() magic
> is in the linker (by extracting the __em_js_* Javascript source code
> strings, and then "somehow" providing the C function import). Any ideas
> what I'm missing?
>
> Thanks!
> -Floh.
>
>
>
>
>
>
--
You received this message because you are subscribed to the Google Groups
"emscripten-discuss" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/emscripten-discuss/454df6be-5e2c-4989-8451-25382c995de0n%40googlegroups.com.
