[std.process] get Pid class by Process ID?

[Jonathan Villa via Digitalmars-d-learn]

Hi everyone,

Is it possible to get a Pid (class) from a process id (int)?.
I need to use the wait function from std.process but it asks for 
a Pid, and I have only the process id (integer).

auto pd = new Pid(processID); // doesn't work

I want to verify that the parent process is still alive, if it 
doesn't, this child process shall be terminated.

Currently, I'm passing the parent process ID by arguments and I 
need a cross-OS way (if possible).

Thanks in advance.