Undefined - error

[Jai Kumar]

package main

import "os"

import "image"

func main() {

    aImg, _ := os.Open("foo.jpg")

    defer aImg.Close()

    decodedImg, _, _ := image.Decode(aImg)

    doSomething(decodedImg)

}

func doSomething(dImg Image) string {

    return "foobar"

}

When I run this it throws error:

prog.go:12: undefined: Image

you can see it at http://play.golang.org/p/wVPMCvg5hD 

What am I doing wrong?

I am sure it must be a stupid question, image.Decode returns type Image, so I should be able to use it?

[Jan Mercl]

On Sep 20, 2012 7:32 PM, "Jai Kumar" <jaiva...@gmail.com> wrote:
>
> What am I doing wrong?

The mighty Gopher kills a kitten whenever an error is ignored.

-j

[Adam Gray]

http://play.golang.org/p/J2QnS2tKeL

--
 
 

[Jai Kumar]

You are right, but I have not gotten the award of being "gopher" yet. A newbie trying to learn go.

Changed the code to 

package main

import "os"

import "image"

import "fmt"

func main() {

    aImg, e := os.Open("foo.jpg")

    if e != nil {

     fmt.Println(e)

    }

    defer aImg.Close()

    decodedImg, _, err := image.Decode(aImg)

    if err != nil {

     fmt.Println(err)

    }

    doSomething(decodedImg)

}

func doSomething(dImg Image) string {

    return "foobar"

}

[minux]

On Sep 21, 2012 1:32 AM, "Jai Kumar" <jaiva...@gmail.com> wrote:
>
> package main
> import "os"
> import "image"

you forgot to import _ "image/jpg", or you won't be able to decode jpeg picture.

>
> func main() {
>     aImg, _ := os.Open("foo.jpg")

blindly ignoring the error is the sign of a very bad style (if not the worst)

>     defer aImg.Close()
>     decodedImg, _, _ := image.Decode(aImg)

>     doSomething(decodedImg)
> }
>
> func doSomething(dImg Image) string {

should use image.Image instead of Image

[Jai Kumar]

Per Jan, changed the code again

see  http://play.golang.org/p/IlahQDwaGy 

[Jai Kumar]

Thank you Adam. Sorry for the silly question ;)

[Jai Kumar]

Thanks minux. I am checking the error in the actual code. It was just a test code I put on play.golang and did not paste the whole code. Anyway I appreciate you reminding about error checking and I will continue doing that.

[Andrew O'Neill]

You need to add the package name in front of Image

func doSomething(dImg image.Image) string {

Andrew

On Thu, Sep 20, 2012 at 1:32 PM, Jai Kumar <jaiva...@gmail.com> wrote:

--