How to include multiple emscripten libraries with multiple preloaded MEMFS filesystems

I have to include multiple libraries for a project - I've already succeeded in including multiple emscripten libraries but I cannot seem to access the preloaded MEMFS filesystem in the 2nd one.In the second library I use the --embed-file parameter in the linker to embed a whole directory with the JS file output but when I access the files in the web console via FS.stat()I cannot access any file that was embedded.Has anyone faced the same issue?...Read more

emscripten - How does one use the HACL* wasm library?

The nice folks over at project everest compiled a formally verified cryptographic library known as HACL* to web assembly. Unfortunately there are no examples of using the code defined here.I tested the code with Version 71.0.3578.98 (Official Build) (64-bit) of Chrome. Here is in essence what I attempted on the client in order to get a working example. var module = HaclLoader().then(function(m) { var state_buffer = new ArrayBuffer(32); var state = new Uint32Array(state_buffer); var message_buffer = new ArrayBuffer(32);...Read more

Getting Emscripten streaming audio to work

I'm trying to get SoLoud audio engine working with Emscripten, and it's acting rather strangely. As an experiment, I'm playing a 500ms sine wave.With a 2048 sample buffer, the latency is around a second or more, and what comes out is 25ms of sine wave. If I reduce the buffer down to 256 samples, the latency gets a bit better (still bad), and the output grows to around, but not exactly, 500ms, and the sound is not clean by any means. This was with firefox; chrome is silent.The emscripten/tests/sdl_audio* tests all use sdl_mixer instead of the st...Read more

Compile issue with Emscripten on Windows 7

According to the official documentation, I need to install Python 2.X, Node.js (0.7.3 or above), gcc 4.6, and clang 3.2. And indeed, they are all installed.Edit: Ok, I've updated this with a much simpler test case, which also fails.hello.cpp#include <iostream>using namespace std;int main (){ cout << "Hello World!"; return 0;}My attempt to compile using:For Google's sake, the error message is: IOError: [Errno 2] No such file or directory: 'c:\users\jonathan\appdata\local\temp\emscripten_temp_7q2hkb\libcxx\libcxx.bc'Why is this Ems...Read more

emscripten - How to access WebAssembly linear memory from C/C++

I'm writing a small C program intended to be compiled to wasm w/ emcc and run in a web browser. Because wasm exported functions can only accept simple number values as parameter inputs and return values, I need to share memory between the JavaScript API and the compiled WebAssembly code in order to access more complex data types like strings or char arrays. The problem is that I can't for the life of me figure out how to access WebAssembly linear memory from inside of my C program.My ultimate goal is to be able to read strings initialized in Ja...Read more

asm.js - Disable linking libc in emscripten

I'm curious if it's possible to have emscripten build a binary without libc.If I have simple.c:int add1(int x) { return x + 1;}And I don't want to include any of libc, is that possible?My best attempt so far has been:emcc simple.c -s NO_FILESYSTEM=1 -s DISABLE_EXCEPTION_CATCHING=1 -s DEFAULT_LIBRARY_FUNCS_TO_INCLUDE='[]' -s LIBRARY_DEPS_TO_AUTOEXPORT='[]' -s EXPORTED_FUNCTIONS='["add1"]' -s USE_SDL=0 -o simple.js -nostdlibBut the generated output still includes symbols for malloc, string conversion routines, and so on.I'm also interested in ...Read more

emscripten - Emscript only change .wasm and .js file after recompile

I worked through the tutorial compiling from C/C++ to WebAssembly. Under point "Calling a custom function defined in C" I have to edit the .html output after compiling. How to avoid emcc from override the .html output if I would recompile .cpp?The cause of avoiding to override .html output is, that I don't want to edit the html after recompiling. Because I think the glue code doesn't change if I only edit inside myFunction.void EMSCRIPTEN_KEEPALIVE myFunction(int argc, char ** argv) { printf("MyFunction Called Edits\n");}...Read more

webassembly - Emscripten generated HTML file does not work when opened, wasm binary must be preloaded

I am able to correctly compile my helloWorld.c file:#include <stdio.h>int main(int argc, char ** argv) { printf("Hello World\n");}using the command: emcc helloWorld.c -s WASM=1 -o helloWorld.htmlHowever when I open the file helloWorld.html, the follow error appears on the page: on the web, we need the wasm binary to be preloaded and set on Module['wasmBinary']. will do that for you when generating HTML (but not JS) abort("on the web, we need the wasm binary to be preloaded and set on Module['wasmBinary']. will do th...Read more

Is there a reasonable way to create a webassembly "static library" in a multi-module build for emscripten

I am converting a large C++ application for run in a webassembly environment. The build is organized into modules and each module sub-project creates a static or a dynamic library.From what I have read there is no "ABI" yet standardized for "wasm" modules for dynamic-linking into the browser runtime engine, so at present dynamic linking of pre-compiled and linked libraries is not yet supported.But in the case of static libraries they are just collections of pre-compiled "intermediate" "object" code which are converted to distribution code in th...Read more

webassembly - How do I set up a basic C++/C compile, and then link script for emscripten builds

This test if in preparation for writing a more fully fledged build module. But I need to sus out the basics first. The desire to: - build all the "object files" output to an output folder - link them into a distributable "wasm" binary and format an html page and output them to a "dist" folder.I looked at the manual in:'s not as intuitive or explicitly spelled out as one would want.Below is my current simple test build.#!/bin/bash# set emscripten toolchain paths ...Read more

How to save files from C to browser storage with emscripten

The game engine that I'm using to run my game in the browser runs lua and from my game i save files using normal fopen / write / fclose. The engine C/C++ code is compiled to JS through emscripten. What is a good way to get these file writes to end up in local storage, or some other in browser cache location? I have searched the web and looked at the documentation but information is very sparse, I have not found any clear answers to how this is supposed to work.A previous contributor to the game engine added a js library to the emscripten build,...Read more