Have a variable in images path in Sass?

I want to have one variable that contains the root path to all my images in my CSS file. I can't quite figure out if this is possible in pure Sass (the actual web project is not RoR, so can't use asset_pipeline or any of that fancy jazz).

Here's my example that doesn't work. On compile it balks at first instance of variable in the background url property saying ("Invalid CSS after "..site/background": expected ")").

Defining the function to return the path:

//Vars
$assetPath : "/assets/images";

//Functions
@function get-path-to-assets($assetPath){
  @return $assetPath;
}

Using the function:

body {
  margin: 0 auto;
  background: url($get-path-to-assets/site/background.jpg) repeat-x fixed 0 0;
  width: 100%; }

Any help would be appreciated.

Have you tried the Interpolation syntax?

background: url(#{$get-path-to-assets}/site/background.jpg) repeat-x fixed 0 0;

No need for a function:

$assetPath : "/assets/images";

...

body {
  margin: 0 auto;
  background: url(#{$assetPath}/site/background.jpg) repeat-x fixed 0 0;
  width: 100%; }

See the interpolation docs for details.

Was searching around for an answer to the same question, but think I found a better solution: http://blog.grayghostvisuals.com/compass/image-url/

Basically, you can set your image path in config.rb and you use the image-url() helper

Adding something to the above correct answers. I am using netbeans IDE and it shows error while using url(#{$assetPath}/site/background.jpg) this method. It was just netbeans error and no error in sass compiling. But this error break code formatting in netbeans and code become ugly. But when I use it inside quotes like below, it show wonder!

url("#{$assetPath}/site/background.jpg")

We can use relative path instead of absolute path:

$assetPath: '~src/assets/images/';
$logo-img: '#{$assetPath}logo.png';
@mixin logo {
  background-image: url(#{$logo-img});
}

.logo {
    max-width: 65px;
    @include logo;
 }