Fix wrong c string returned from native lib

[andelf]

SUMMARY

Fixes #593

Checks

Bugfix

• [x] Related issues linked using fixes #number
• [ ] Integration tests added
• [ ] Architecture Decision Record added if design changes necessary
• [x] Formatting checked

ADDITIONAL INFORMATION

[TimoKramer]

@TimoKramer For some reason the tests have not been run on this PR, not sure why.

It depends on the person opening the PR being logged into circleci