Learning Perl on Win32 Systems

Win32::Process

The most flexible way of starting a process on Windows NT is to use the Win32::Process module.^[88] Using this module, you can select whether or not you want to wait for the child process to run to completion, configure priorities, and suspend or resume processes.

Even though we haven’t covered all of the relevant concepts, we are going to run through a Win32::Process example.

As shown, theWin32::Process module contains a method (subroutine) called Create that does all the work of creating a process:

use Win32::Process;
Win32::Process::Create($Process, 
		"c:\\nt\\system32\\notepad.exe",
		"notepad",
		0,
		DETACHED_PROCESS,
		".") || die "Create: $!";

This code creates an asychronous instance of Notepad. Let’s take a look at the parameters. The first parameter $Process is a scalar reference that receives the process object if the call succeeds. We’ll discuss references in Chapter 18, but for now, you can just think of it as a parameter that receives output.

The second argument is a fully qualified (system-dependent) path to the executable. The third argument is the command line passed to the program. In this case, we’re just invoking Notepad without any documents or options. The next argument specifies whether or not the new process inherits handles from the parent process (the Perl program). A value of one indicates that the process inherits any inheritable open handle in the parent process. Inheritable handles include I/O handles, socket handles, synchronization handles, and ...