Module.cwrap not finding symbols

[j4m3z0r]

Have been trying to get Module.cwrap to work. Followed the instructions on https://github.com/kripken/emscripten/wiki/Interacting-with-code -- I ran

./emcc tests/hello_function.cpp -o function.html

Loaded that in Chrome, entered

int_sqrt = Module.cwrap('int_sqrt', 'number', ['number'])

into the Javascript Console and got this error:

Assertion failed: Cannot call unknown function int_sqrt (perhaps LLVM optimizations or closure removed it?):
Error
    at abort (file:///tmp/function.html:568:32)
    at assert (file:///tmp/function.html:575:5)
    at getCFunc (file:///tmp/function.html:612:56)
    at Object.cwrap (file:///tmp/function.html:658:14)
    at <anonymous>:2:19
    at Object.InjectedScript._evaluateOn (<anonymous>:505:39)
    at Object.InjectedScript._evaluateAndWrap (<anonymous>:464:52)
    at Object.InjectedScript.evaluate (<anonymous>:400:21)

[j4m3z0r]

(re-posting from right github account -- sorry. Now I can close!)

Ok, so this can probably be reduced to a documentation bug. If you invoke emcc like so:

./emcc -s EXPORTED_FUNCTIONS="['_int_sqrt']" -o /tmp/function.html tests/hello_function.cpp

Then it does indeed work as advertised. I assume that something has changed in the behavior of either LLVM or Emscripten that causes this to be necessary now, whereas previously these functions were not stripped.

Probably just updating the documentation on https://github.com/kripken/emscripten/wiki/Interacting-with-code to cite the EXPORTED_FUNCTIONS argument as mandatory for this kind of thing will suffice.

[kripken]

This is probably LLVM doing more aggressive code elimination now. Thanks, i'll update the docs there about this.