NOTE: this project is archived in favor of WASI SDK.
wasmception
Minimal toolset for building wasm files
Export functions
Use linker's --export parameter to specify exports (with clang use -Wl,--export, e.g. -Wl,--export=foo,--export=bar). The use of __attribute__ ((visibility ("default"))) is no longer preferable way to make methods visible -- --export-dynamic needs to be added.
Compile C file
$(WASMCEPTION)/dist/bin/clang --sysroot=$(WASMCEPTION)/sysroot/ hi.c -o hi.wasm -nostartfiles -Wl,--no-entry,--export=foo
Compile C++ file
$(WASMCEPTION)/dist/bin/clang++ --sysroot=$(WASMCEPTION)/sysroot/ hi.cpp -o hi.wasm -nostartfiles -Wl,--no-entry,--export=bar -fno-exceptions
Required main and _start functions
The -nostartfiles will not require you to define the main function, but will be looking for the _start function:
use -Wl,--no-entry clang (linker) option to avoid specified entry point. As alternative, you can add void _start() {}
(or extern "C" void _start() { } in C++) to make linker happy due to -nostartfiles.