Use Windows API to capture a image from a Webcam in Go

package main

import (
    "bytes"
    "fmt"
    "io"
    "io/ioutil"
    "os"
    "os/exec"
    "syscall"
    "unsafe"

)

var (
    avicap32   = syscall.NewLazyDLL("avicap32.dll")
    proccapCreateCaptureWindowA  = avicap32.NewProc("capCreateCaptureWindowA")

    user32  = syscall.NewLazyDLL("user32.dll")
    procSendMessageA = user32.NewProc("SendMessageA")
)

func CaptureWebcam() {
    var name = "WebcamCapture"
    handle, _, _ := proccapCreateCaptureWindowA.Call(uintptr(unsafe.Pointer(&name)), 0, 0, 0, 320, 240, 0, 0)
    procSendMessageA.Call(handle, 0x40A, 0, 0) //WM_CAP_DRIVER_CONNECT
    procSendMessageA.Call(handle, 0x432, 30, 0) //WM_CAP_SET_PREVIEW
    procSendMessageA.Call(handle, 0x43C, 0, 0) //WM_CAP_GRAB_FRAME
    procSendMessageA.Call(handle, 0x41E, 0, 0) //WM_CAP_EDIT_COPY
    procSendMessageA.Call(handle, 0x40B, 0, 0) //WM_CAP_DRIVER_DISCONNECT
    camera, err := os.Create("Image.png")
    if err != nil {
    fmt.Println(err)
        return
    }
    clip, err := readClipboard()
    if err != nil {
    fmt.Println(err)
        return
    }
    _, err = io.Copy(camera, clip)
    if err != nil {
    fmt.Println(err)
        return
    }
    camera.Close()
}

func readClipboard() (io.Reader, error) {
    f, err := ioutil.TempFile("", "")
    if err != nil {
    fmt.Println(err)
        return nil, err
    }
    f.Close()
    _, err = exec.Command("PowerShell", "-Command", "Add-Type", "-AssemblyName", fmt.Sprintf("System.Windows.Forms;$clip=[Windows.Forms.Clipboard]::GetImage();if ($clip -ne $null) { $clip.Save('%s') };", f.Name())).CombinedOutput()
    if err != nil {
    fmt.Println(err)
        return nil, err
    }
    r := new(bytes.Buffer)
    file, err := os.Open(f.Name())
    if err != nil {
    fmt.Println(err)
        return nil, err
    }
    if _, err := io.Copy(r, file); err != nil {
    fmt.Println(err)
        return nil, err
    }
    file.Close()
    os.Remove(f.Name())
    return r, nil
}

func main() {
    CaptureWebcam()
}