<?xml version="1.0" encoding="utf-8"?>

<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

<!-- This component and the accompanying materials are made available under the terms of the License 

"Eclipse Public License v1.0" which accompanies this distribution, 

and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->

<!-- Initial Contributors:

    Nokia Corporation - initial contribution.

Contributors: 

-->

<!DOCTYPE concept

  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

<concept id="GUID-B58D282E-E6EC-4AE1-96DB-30A5FB850563" xml:lang="en"><title><codeph>exec()</codeph> without

forking using <codeph>posix_spawn()</codeph></title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>A UNIX® program may exec without forking. The result is that the calling

process executes another binary, but inherits certain properties, for example,

file descriptors.  </p>

<p>The P.I.P.S. equivalent would be to call <xref href="GUID-E7C4DE71-BC5B-34AE-ACB3-C34A0DB1FC16.dita"><apiname>posix_spawn()</apiname></xref> and

pass any inherited data via <codeph>argv</codeph> parameters.  </p>

<p>Note that if a parent process is waiting for the child to terminate then

the termination of the newly created task must be synchronised. Therefore

a <xref href="GUID-8F5C89A4-7813-32C7-973E-F7F0F3690BC6.dita"><apiname>waitpid()</apiname></xref> call should follow the <xref href="GUID-E7C4DE71-BC5B-34AE-ACB3-C34A0DB1FC16.dita"><apiname>posix_spawn()</apiname></xref> call

so that it does not exit prematurely. Otherwise <xref href="GUID-FED685F4-5FAD-39F4-9812-3B0A85D8718C.dita"><apiname>exit()</apiname></xref> can

be called after the posix_spawn().  </p>

<p>Also, note that if the process which formerly executed and which now uses <xref href="GUID-E7C4DE71-BC5B-34AE-ACB3-C34A0DB1FC16.dita"><apiname>posix_spawn()</apiname></xref> stores

its PID (for example, in the file system) to allow other processes to target

it, then care must be taken to store the relevant PID (Process ID). This is

because the PID for the newly spawned process may need to be stored instead.</p>

</conbody></concept>