I got the similar error message with scanning C++ program without using MSBuild. Here is my command. Without using MSBuild, it does NOT require to execute build-wrapper prior to sonar-scanner. Is it correct? I have a sub-folder named example which contains a bunch of C++ source files.
sonar-scanner.bat -D"sonar.projectKey=cpp-restfullibrary" -D"sonar.sources=example" -D"sonar.host.url=http://localhost:9000" -D"sonar.login=d5f545bf8bd6988d33e75c34e1ccee4ba7a49b0d" -X
I thank you in advance for your help.