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Practical WebAssembly

Converting WASM into C

Learn how to convert WASM into C using the wasm2c command.

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WABT has a wasm2c converter that converts WASM into C source code and a header.

Let’s create a simple.wat file:

Shell
touch simple.wat

Add the following contents to simple.wat:

C++
(module
  (func $uanswer (result i32)
    i32.const 22
    i32.const 20
    i32.add
  )
)

wat here defines a uanswer function that adds 22 and 20 to give 42 as the answer. Let's create a WebAssembly binary using wat2wasm:

Shell
/path/to/build/directory/of/wabt/wat2wasm simple.wat -o simple.wasm

This generates the simple.wasm binary. Now, convert the binary into C code using wasm2c:

Shell
(module
  (func $uanswer (result i32)
    i32.const 22
    i32.const 20
    i32.add
  )
)

This generates simple.c and simple.h.

Note: Both simple.c and simple.h might look huge. Remember this is an autogenerated file and it includes all the ...