# mangOH green: golang and positioning
**URL:** https://mangoh.discourse.group/t/mangoh-green-golang-and-positioning/1533
**Category:** mangOH Green
**Created:** [June 9, 2018, 10:39pm UTC](https://mangoh.discourse.group/t/mangoh-green-golang-and-positioning/1533 "2018-06-09T22:39:18Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@magiconair](https://mangoh.discourse.group/u/magiconair)
#### Post date: [June 9, 2018, 10:39pm UTC](https://mangoh.discourse.group/t/mangoh-green-golang-and-positioning/1533/1 "2018-06-09T22:39:18Z")
Hi,
I am trying to access the positioning service from a Go app and I’m stuck on starting the positioning service. Generally, how do you use Legato services from 3rd party apps (in my case a Go app)?
I am using `bundles` to package the app or just copy the binary to the mangOH green to see whether it works at all.
When I run the app I get `le_posCtrl_ConnectService() not called for current thread`. I’m assuming that I need to start the positioning service somehow and that this is achieved through the `bindings` section in the `.adef` file.
```auto
$ cat Makefile
CC=/opt/swi/y17-ext/sysroots/x86_64-pokysdk-linux/usr/libexec/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/4.9.1/gcc
build: clean
CC=$(CC) GOOS=linux GOARCH=arm GOARM=7 CGO_ENABLED=1 go build
scp: build
scp gps root@192.168.2.2:
instapp: build
mkapp -v -t wp750x gps.adef
instapp gps.wp750x.update 192.168.2.2
ifgen:
ifgen --gen-interface --gen-client --gen-local $(LEGATO_ROOT)/interfaces/positioning/le_pos.api
ifgen --gen-interface --gen-client --gen-local $(LEGATO_ROOT)/interfaces/positioning/le_posCtrl.api
clean:
rm -f *.o
rm -f gps
```
```auto
$ cat gps.adef
sandboxed: false
version: 1.0.0
bundles:
{
file:
{
[x] gps /bin/gps
}
}
processes:
{
run:
{
( gps )
}
}
```
```auto
$ cat /go/src/gps/main.go
package main
/*
#cgo CFLAGS: -I/legato/framework/c/inc
#cgo LDFLAGS: -L/legato/build/wp750x/framework/lib -llegato
#include
#include "legato.h"
#include "le_pos_interface.h"
#include "le_posCtrl_interface.h"
*/
import "C"
import "log"
import "time"
func main() {
log.Print("Starting gps")
// this never returns
// log.Print("Calling le_posCtrl_ConnectService()")
// C.le_posCtrl_ConnectService()
log.Print("Calling le_posCtrl_Requst()")
ref := C.le_posCtrl_Request()
if ref == nil {
log.Fatal("Cannot activate positioning service")
}
defer C.le_posCtrl_Release(ref)
var lat, lon, acc C.int
for {
log.Println("Calling le_pos_Get2DLocation")
res2 := C.le_pos_Get2DLocation(&lat, &lon, &acc)
log.Printf("le_pos_Get2DLocation: res: %d lat: %d lon: %d acc: %d\n", res2, lat, lon, acc)
time.Sleep(500*time.Millisecond)
}
}
```
Running `make` and copying the file to 192.168.2.2 and running it returns
```auto
Jun 9 22:30:00 swi-mdm9x15 user.emerg Legato: *EMR* | _UNKNOWN_[8337]/framework T=main | LE_FILENAME GetCurrentSessionRef() 320 | le_posCtrl_ConnectService() not called for current thread
```
Adding a call to `le_posCtrl_ConnectService()` at the start never returns.
I’ve then tried adding generic bindings to the `gps.adef` file but with no success.
```auto
...
bindings:
{
*.le_posCtrl -> positioningService.le_posCtrl
*.le_pos -> positioningService.le_pos
}
```
`mkapp -v -t wp750x gps.adef` returns
```auto
/go/src/gps/gps.adef:27:6: error: No such client-side pre-built interface 'le_posCtrl'.
```
I’m probably missing something obvious or this isn’t possible. Any help is greatly appreciated.
Update 1: I am using Legato 16.10.3 on a mangOH green with a WP750x
---
### Author:  [@dfrey](https://mangoh.discourse.group/u/dfrey)
#### Post date: [June 11, 2018, 5:02pm UTC](https://mangoh.discourse.group/t/mangoh-green-golang-and-positioning/1533/2 "2018-06-11T17:02:14Z")
Have you tried asking on the [Legato forum](https://forum.legato.io)?
---
### Author:  [@magiconair](https://mangoh.discourse.group/u/magiconair)
#### Post date: [June 11, 2018, 5:03pm UTC](https://mangoh.discourse.group/t/mangoh-green-golang-and-positioning/1533/3 "2018-06-11T17:03:02Z")
Actually - no 🙂 I’m somewhat new to this environment. I’ll try thx.