gvim - fatal error: can't find import: fmt?

I have setup go related environment variables in my ~/.bashrc as follows

GOROOT=$HOME/go
GOOS=linux
GOARCH=amd64
GOBIN=$HOME/bin
export GOROOT GOOS GOARCH GOBIN PATH

When I compile from vi (:make) in terminal, everything is fine. However, when I do the same from gvim (window), I was getting

fatal error: can't find import: fmt

A quick google search pointed me to this

So, gvim is not seeing those environment variables. I confirm in gvim with

:echo $GOROOT

Reports an empty string. So I edit $MYVIMRC (:e $MYVIMRC) and add the following

:let $GOROOT='/home/amitava/go'
:let $GOARCH='amd64'
:let $GOOS='linux'

Worked like a charm!

My exploration of Google "go" programing language

1. return
Named return variables are available within the scope of the function. Consider the following funciton

func SomeFunc() (foo int, bar int) {
  // notice how foo and bar is already defined in the body and a return w/no arg returns those values
  foo = 10
  bar = 20
  return // compiler knows it has to return foo & bar
)

2. Type Assertion (ala dynamic_cast)
Given an interface type, it can be coerced to another interface type (at runtime) provided the underlying type supports both the interfaces

Look for type assertion here (Go For C++ Programmers). You have to scroll down to the relevant section. Just use browser search - use type assertion

3. defer - a piece of code to run when the surrounding function returns. Cool feature! See Here

4. dot import

Import declaration          Local name of Sin
import . "lib/math"         Sin (as opposed to math.Sin)

See go-doc - import

Xen block device

While reading "The Book of Xen", I ran into a snag with attaching a block device in dom0

# xm block-attach 0 duncan. img /dev/xvda1 w 0

I am expecting /dev/xvda1 to show up now, but it doesn't. As suggested in the book, I try

# /mknod /dev/xvda b 220 0

Doesn't work (btw, the book has a typo, it should be 202 not 220)

Turns out, the xenblk kernel module was not loaded. Do this
# modprobe xenblk
# lsmod | grep xenblk

Now xm block-attach works like a charm