Building go binding inside Termux (Android ARM)

[Ronoaldo Pereira]

Hi!

I am trying to build a small utility using tesseract from a Go program, and instead of calling a subprocess and initializing the OCR engine every time I plan to run the OCR from a Go routine.

I have this small code that uses a binding to tesseract:

$ cat main.go 

package main

import (

        "io/ioutil"

        "os"

        "fmt"

        "log"

        "github.com/otiai10/gosseract"

)

func main() {

        client := gosseract.NewClient()

        defer client.Close()

        b, err := ioutil.ReadAll(os.Stdin)

        if err != nil {

                log.Fatal("Error loading image from stdin: %v", err)

        }

        if err := client.SetImagesFromBytes(b); err != nil {

                log.Fatal("Invalid image format from stdin: %v", err)

        }

        hocr, err := client.HOCR()

        if err != nil {

                log.Fatal("Error performing hOCR: %v", err)

        }

        fmt.Println(hocr)

}

When I try to compile using the version 4.1.1 of tesseract (from pkg install tesseract inside Termux) I get this errors:

# github.com/otiai10/gosseract

/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: /data/data/com.termux/files/usr/lib/libtesseract.so: undefined reference to `omp_get_thread_num'

/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: /data/data/com.termux/files/usr/lib/libtesseract.so: undefined reference to `__kmpc_serialized_parallel'

/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: /data/data/com.termux/files/usr/lib/libtesseract.so: undefined reference to `__kmpc_push_num_threads'

/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: /data/data/com.termux/files/usr/lib/libtesseract.so: undefined reference to `__kmpc_for_static_init_4'

/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: /data/data/com.termux/files/usr/lib/libtesseract.so: undefined reference to `__kmpc_end_serialized_parallel'

/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: /data/data/com.termux/files/usr/lib/libtesseract.so: undefined reference to `__kmpc_global_thread_num'

/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: /data/data/com.termux/files/usr/lib/libtesseract.so: undefined reference to `__kmpc_fork_call'

/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: /data/data/com.termux/files/usr/lib/libtesseract.so: undefined reference to `__kmpc_for_static_fini'

clang-10: error: linker command failed with exit code 1 (use -v to see invocation)

I don't know if this issue is in my code, the lib binding or the Termux build of tesseract. Any help to dissect this will be apreciated!

Best regards,

[Ronoaldo Pereira]

When testing the code on PC there were errors in the Go code, but they are unrelated to the build errors from libtesseract.so:

```

package main

import (
       "io/ioutil"
       "os"
       "fmt"
       "log"

       "github.com/otiai10/gosseract"
)

func main() {
       client := gosseract.NewClient()
       defer client.Close()

       b, err := ioutil.ReadAll(os.Stdin)
       if err != nil {
               log.Fatal("Error loading image from stdin: %v", err)
       }

       if err := client.SetImageFromBytes(b); err != nil {

               log.Fatal("Invalid image format from stdin: %v", err)
       }

       hocr, err := client.HOCRText()

       if err != nil {
               log.Fatal("Error performing hOCR: %v", err)
       }
       fmt.Println(hocr)
}

```

Since I could build and run this program on my PC with no errors, it seems to be related to the build toolchain on android. Apologise for the confusion here! I filled a bug report on termux-packages repository: https://github.com/termux/termux-packages/issues/5946

Best Regards,