"ERROR:root:cwrap]': No such file or directory"

[DragonOsman]

I tried to follow the int_sqrt example here: https://kripken.github.io/emscripten-site/docs/porting/connecting_cpp_and_javascript/Interacting-with-code.html but I got an error saying

ERROR:root:cwrap]': No such file or directory ("cwrap]'" was expected to be an input file, based on the commandline arguments provided)

Could someone please help me out here?

[kripken]

Probably an escaping issue or a typo in the command you wrote. What was the command, and in what shell?

[kripken]

(By the error message, ("cwrap]'", I suspect you need to move the quotes around, to ("cwrap"]')

[DragonOsman]

I did it in the correctly set-up terminal (with the environment set) and I ran the command with double-quotes around "cwrap".

This was the command I ran, in both WSL and in regular Windows mode (with the correct modifications made to the command):

./emcc tests/hello_function.cpp -o function.html -s EXPORTED_FUNCTIONS='["_int_sqrt"]' -s EXTRA_EXPORTED_RUNTIME_METHODS='["ccall", "cwrap"]'

I can get ccall to work, but not cwrap. I tried this example, which uses ccall but not cwrap, and got it to work: https://developer.mozilla.org/en-US/docs/WebAssembly/C_to_wasm#Calling_a_custom_function_defined_in_C .

Edit to add: The source emsdk_env.bat (Windows) and source ./emsdk_env.sh (Linux/WSL (?)) command doesn't work either; I get an error indicating that it doesn't know the command.

[DragonOsman]

So no one is able to help me out?

Again, I followed the aforementioned tutorial and called cwrap exactly as it says and I still got that error. I need help on this.

Also, there's that other issue I opened about porting my web server application to WebAssembly as a module to use on the backend through Node. The code for the app is here. I also wrote an asynchronous version of the code, but on that one I'm having trouble with making the client code asynchronous because of the code in cache_storage::query() that I need to convert to be asynchronous.

And because this uses Beast which is based of ASIO (which doesn't support WebAssembly), I need to know how to port ASIO to WebAssembly as well.

[kripken]

I don't know much about WSL, but this seems like an escaping issue. Might be worth trying all the other possibilities, like -s 'X=["y"]' for example (note ' are around the key, the equals, and the value).

[DragonOsman]

Just now, I again tried to run this same command:

emcc tests/hello_function.cpp -o function.html -s EXPORTED_FUNCTIONS='["_int_sqrt"]' -s EXTRA_EXPORTED_RUNTIME_METHODS='["ccall", "cwrap"]'

exactly as documented in the tutorial, but I got this same error again:

ERROR:root:cwrap]': No such file or directory ("cwrap]'" was expected to be an input file, based on the commandline arguments provided)

I'm sure I didn't make any mistakes. I just copy-pasted the command as is from the tutorial here. There shouldn't be any mistakes. I ran this command:

emcc tests/hello_function.cpp -o function.html -s EXPORTED_FUNCTIONS='["_int_sqrt"]' -s EXTRA_EXPORTED_RUNTIME_METHODS='["ccall", "cwrap"]'

Also, just now, I tried to build my currency_converter.cpp app with this command:

em++ -std=c++17 -Wall -pedantic -D variant_CONFIG_SELECT_VARIANT=variant_VARIANT_NONSTD -s DISABLE_EXCEPTION_CATCHING=0 -I C:/Jinja2Cpp/install_x64/include -I C:/json/single_include -I C:/boost_1_68_0/ -c currency_converter.cpp -L C:/Jinja2Cpp/install_x64/lib/static/jinja2cpp.lib -L C:/boost_1_68_0/lib64-msvc-14.1/libboost_system-vc141-mt-x64-1_68.lib -lpthread -o currency_converter.js

and it didn't generate a .wasm file. I tried entering the command node currency_converter.js as well, but I got this error:

E:\programming\visual_studio_2017\Projects\currency_converter\currency_converter\currency_converter.js:1
(function (exports, require, module, __filename, __dirname) { BC��5�
                                                                ^

SyntaxError: Invalid or unexpected token
    at createScript (vm.js:80:10)
    at Object.runInThisContext (vm.js:139:10)
    at Module._compile (module.js:599:28)
    at Object.Module._extensions..js (module.js:646:10)
    at Module.load (module.js:554:32)
    at tryModuleLoad (module.js:497:12)
    at Function.Module._load (module.js:489:3)
    at Function.Module.runMain (module.js:676:10)
    at startup (bootstrap_node.js:187:16)
    at bootstrap_node.js:608:3

And I tried to open the .js file as well. There's nothing to show, though. No file coming in Visual Studio. Is there something I missed in the command I entered? The app source code is on GitHub here.

[DragonOsman]

On second thought, It could be because I have to give special treatment to std::shared_ptr when trying to compile to WebAssembly. I'll have to read again about how to do that.

Also, if I want to pass API keys as environment variables to use in my WebAssembly application, and I want to use it as a Node.js module, should I use ENV in my Node.js code like this?

Module.preRun.push(function() {ENV.my_key = "value"})

Edit: If I want to use a std::shared_ptr and I have it like this:

std::make_shared<listener>(ioc, tcp::endpoint{ address, port }, doc_root)->run();

how do I do it using EMSCRIPTEN_BINDINGS? I also need to know about how to do it with std::enable_shared_from_this<>.

Edit: @kripken I need some help here if you're free. I can't generate .wasm code at all for my app. Code is here and compilation command I used is:

em++ -std=c++17 -Wall -pedantic -D variant_CONFIG_SELECT_VARIANT=variant_VARIANT_NONSTD -I C:/Jinja2Cpp/install_x64/include -I C:/json/single_include -I C:/boost_1_68_0/ -I C:/Users/Osman/emsdk/emscripten/1.38.18/system/include/ -c currency_converter.cpp -s WASM=1 -s DISABLE_EXCEPTION_CATCHING=0 -s USE_PTHREADS=1 -L C:/Jinja2Cpp/install_x64/lib/static/jinja2cpp.lib -L C:/boost_1_68_0/lib64-msvc-14.1/libboost_system-vc141-mt-x64-1_68.lib -lpthread -o currency_converter.js

And as I said before, just a bit ago I ran this command (copy-pasted it as is from the Emscripten tutorial on ccall and cwrap, except I used emcc instead of ./emcc):

emcc tests/hello_function.cpp -o function.html -s EXPORTED_FUNCTIONS='["_int_sqrt"]' -s EXTRA_EXPORTED_RUNTIME_METHODS='["ccall", "cwrap"]'

And it still gave me that same error as before.

In my compilation command for my app, I'm also going to try it by putting the -s flags after -o currency_converter.js flag and see if it helps. Also, please let me know if I need to use EMSCRIPTEN_BINDINGS with std::shared_ptr when I'm going to use the WASM module as a Node.js module on the backend. I have my own HTML, CSS and JavaScript files that go with my app and my C++ code is a webserver that serves them up and also does the currency conversion calculation (getting the conversion rates from a currency API by making a GET request). So I'm trying to compile a webserver to WebAssembly, which is why I want to use it with Node.

Edit: Okay, putting the -s stuff after the -o flag didn't help either.

[hainawa]

I've met the same problem.After trying several times,I found it could be resolved by change ' to ":
emcc tests/hello_function.cpp -o function.html -s EXPORTED_FUNCTIONS="['_int_sqrt']" -s EXTRA_EXPORTED_RUNTIME_METHODS="['ccall', 'cwrap']"

[raspiduino]

For someone who export functions in cmake, -sEXPORTED_FUNCTIONS=['_int_sqrt'] -sEXTRA_EXPORTED_RUNTIME_METHODS=['ccall', 'cwrap'] worked for me!

See this StackOverflow post.