Running Python script from C++ code(.NET)

[Gerard Flanagan]

volcano wrote:

> volcano wrote:
> > Hello, folks!
> > A trivial question - I have a working Python script that I have to
> > invoke from C++ code. No fancy stuff - just run the whole script with
> > its parameters. No callbacks, no signalling - nada, just
> > stupid,primitive, straightforward call.
> >
> > And while there is a lot of help on embedding, I could not find out how
> > to run script as a whole.SOS!!!!
>
> Thanks a lot to all of you who cared to answer! Eventually it was
> "::CreateProcess", and it works!
>

I used to find http://pinvoke.net a good resource when I was doing
Active Directory stuff.  Just for interest's sake, cutting and pasting
from the CreateProcess page, the following arcana will start Python (
again from C#, but here you can see the internals at least):

using System;
using System.Runtime.InteropServices;

class Class1
{
	[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
	public struct STARTUPINFO
	{
		Int32 cb;
		string lpReserved;
		string lpDesktop;
		string lpTitle;
		Int32 dwX;
		Int32 dwY;
		Int32 dwXSize;
		Int32 dwYSize;
		Int32 dwXCountChars;
		Int32 dwYCountChars;
		Int32 dwFillAttribute;
		Int32 dwFlags;
		Int16 wShowWindow;
		Int16 cbReserved2;
		IntPtr lpReserved2;
		IntPtr hStdInput;
		IntPtr hStdOutput;
		IntPtr hStdError;
	}

	[StructLayout(LayoutKind.Sequential)]
	public struct PROCESS_INFORMATION
	{
		public IntPtr hProcess;
		IntPtr hThread;
		public int dwProcessId;
		public int dwThreadId;
	}

	[StructLayout(LayoutKind.Sequential)]
	public struct SECURITY_ATTRIBUTES
	{
		public int nLength;
		public IntPtr lpSecurityDescriptor;
		public int bInheritHandle;
	}

	[DllImport("kernel32.dll")]
	public static extern bool CreateProcess(string lpApplicationName,
		string lpCommandLine, ref SECURITY_ATTRIBUTES lpProcessAttributes,
		ref SECURITY_ATTRIBUTES lpThreadAttributes, bool bInheritHandles,
		uint dwCreationFlags, IntPtr lpEnvironment, string
lpCurrentDirectory,
		ref STARTUPINFO lpStartupInfo,
		out PROCESS_INFORMATION lpProcessInformation);

	[STAThread]
	static void Main(string[] args)
	{
		const uint NORMAL_PRIORITY_CLASS = 0x0020;

		bool retValue;
		string Application = @"c:\python\python24\python.exe";
		string CommandLine = "";
		PROCESS_INFORMATION pInfo = new PROCESS_INFORMATION();
		STARTUPINFO sInfo = new STARTUPINFO();
		SECURITY_ATTRIBUTES pSec = new SECURITY_ATTRIBUTES();
		SECURITY_ATTRIBUTES tSec = new SECURITY_ATTRIBUTES();
		pSec.nLength = Marshal.SizeOf(pSec);
		tSec.nLength = Marshal.SizeOf(tSec);

		retValue = CreateProcess(Application,CommandLine,
			ref pSec,ref tSec,false,NORMAL_PRIORITY_CLASS,
			IntPtr.Zero,null,ref sInfo,out pInfo);

	}
}