gcc/libgo/go/os/executable_windows.go

// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package os

import (
	"internal/syscall/windows"
	"syscall"
)

func getModuleFileName(handle syscall.Handle) (string, error) {
	n := uint32(1024)
	var buf []uint16
	for {
		buf = make([]uint16, n)
		r, err := windows.GetModuleFileName(handle, &buf[0], n)
		if err != nil {
			return "", err
		}
		if r < n {
			break
		}
		// r == n means n not big enough
		n += 1024
	}
	return syscall.UTF16ToString(buf), nil
}

func executable() (string, error) {
	return getModuleFileName(0)
}