wazero/examples/allocation/zig

Zig allocation example

This example shows how to pass strings in and out of a Wasm function defined in Zig, built with zig build.

$ go run greet.go wazero
wasm >> Hello, wazero!
go >> Hello, wazero!

greet.zig does a few things of interest:

• Uses @ptrToInt to change a Zig pointer to a numeric type
• Uses [*]u8 as an argument to take a pointer and slices it to build back a string

The Zig code exports "malloc" and "free", which we use for that purpose.

Notes

This example uses @panic() rather than unreachable to handle errors since unreachable emits a call to panic only in Debug and ReleaseSafe mode. In ReleaseFast and ReleaseSmall mode, it would lead into undefined behavior.

If building wasm with a pre-release version of Zig 0.10.0, use -fstage1 to avoid bugs in the new compiler.