CreateAndTerminateProcessWithIL2CPP

Overview

When developing with Unity, if you choose IL2CPP as the scripting backend, it brings along several challenges.

• First, code that relies on C# reflection is not supported. Common libraries like Protocol Buffers and log4net, which use reflection, require modifications.

• Secondly, the System.Diagnostics.Process namespace is also unsupported. If you need to launch an external application, an alternative approach is necessary. Unfortunately, Unity lacks sufficient resources to modify IL2CPP to support Process. The solutions available online are quite scarce, with only one GitHub repository providing a potential workaround. However, this solution is not readily usable due to various issues.

Given this situation, I've developed a method utilizing kernel32 API calls to achieve launching and closing external processes, as well as terminating processes with specific names.

Usage

Here, there's a script called ProcessLauncher which doesn't require inheriting from MonoBehaviour (I inherited it for testing purposes using Update). The key methods are located in the Process Methods region, namely StartExternalProcess, TerminateExternalProcess, and CloseProcessByName.

The StartExternalProcess method can either return a variable of type ProcessInformation or not, depending on your preference. If it does return, you can use the TerminateExternalProcess method with that ProcessInformation to close the specific process. For instance, if you've launched multiple external .exe files, you can selectively close one or more of them based on the ProcessInformation.

Lastly, the CloseProcessByName method involves first creating a process snapshot, then comparing the names to close processes with specific names. Note that the processName variable should include the ".exe" extension. After closing the process, remember to clean up the snapshot.Like this:

var snapshot = CreateToolhelp32Snapshot(2, 0);
CloseProcessByName("cmd.exe", snapshot);
CloseHandle(snapshot);

Regarding the usage of these methods, I've placed them in the Update function. Pressing A will launch two external applications. You should modify this as needed. Pressing B and C will close these external applications based on their process information. Pressing D will close these processes based on their names.

Notice

lpCommandLine is LPTSTR, not LPCTSTR, so the argument cannot be a string constant; it must be a writable array of strings

wchar_t wszCmd[] = L" -arg";
CreateProcess(L"C:\\Program Files\\WinRAR\\WinRAR.exe", wszCmd, ...);

Note that wszCmd[], the content of lpCommandLine, needs a space at the beginning, otherwise it is attached to lpApplicationName.

Other

Here are some relevant links, including forums and repositories. If you find my code helpful, feel free to give it a star.

https://forum.unity.com/threads/solved-il2cpp-and-process-start.533988/

https://github.com/josh4364/IL2cppStartProcess

https://learn.microsoft.com/zh-cn/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessw