Why does IL2CPP run with no error and no output

My unity version is 5.3.4f, and I hava C# script as a.cs and compiled a.exe and it runs OK. Then I use IL2CPP to translate a.exe into C++ compiled exe a_il2cpp.exe with command:

il2cpp.exe --outputpath=a_il2cpp.exe --cachedirectory="obj_cache" generatedcppdir="generated_cpp" a.exe

But it shows no error and no output, do I miss something? I have C++ compiler installed.