# geteuid
> Return the effective numeric user identity of the calling process.
## Usage
```javascript
var geteuid = require( '@stdlib/process/geteuid' );
```
#### geteuid()
Returns the effective numeric user identity of the calling process.
```javascript
var id = geteuid();
```
## Notes
- The function **only** returns an `integer` user identity on POSIX platforms. For all other platforms (e.g., Windows, browsers, and Android), the function returns `null`.
- See [geteuid(2)][geteuid].
## Examples
```javascript
var geteuid = require( '@stdlib/process/geteuid' );
var uid = geteuid();
if ( uid === 0 ) {
console.log( 'Effectively running as root.' );
} else {
console.log( 'uid: %d', uid );
}
```
[geteuid]: http://man7.org/linux/man-pages/man2/geteuid.2.html