Symbian3/SDK/Source/GUID-E65D91AE-482F-5592-B83C-0F29126C2EFA.dita
changeset 0 89d6a7a84779
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-E65D91AE-482F-5592-B83C-0F29126C2EFA.dita	Thu Jan 21 18:18:20 2010 +0000
@@ -0,0 +1,47 @@
+<?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 xml:lang="en" id="GUID-E65D91AE-482F-5592-B83C-0F29126C2EFA"><title>Using Signals to Handle Exceptions </title><prolog><metadata><keywords/></metadata></prolog><conbody><p>Signals provide an alternative method (to checking return values) of handling exceptions or failures. The following example code demonstrates how you can check the return value for a failure and also how you can register a handler for handling the failure asynchronously: </p> <codeblock id="GUID-49B4A39A-34F5-54D1-AD97-5AD50EFD9786" xml:space="preserve">#include &lt;signal.h&gt;
+#include &lt;stdio.h&gt;
+int func()
+    {
+    int success = 1;
+    // function logic
+    // success == 1  - Indicates that the function logic succeeded
+    // success == 0  - Indicates that the function logic failed
+    if(success)
+        return 0;
+    else
+        {
+        raise(SIGUSR1);
+        return -1;
+        }
+    }
+void sighandler(int signum)
+    {
+    if(signum == SIGUSR1)
+        // 'signal' method for checking failure
+        printf(“Error: An error occured in func().”);
+    else
+        printf(“Error: Unknown signal”);
+    }
+int main(void)
+    {
+    int retval = 0;
+    // When SIGUSR1 arrives, invoke sighandler()
+    signal(SIGUSR1,sighandler);
+    retval = func();
+    if(retval == -1)
+        // The return value method used for checking failure
+        printf("Error: An error occured in func().");  
+    }</codeblock> </conbody><related-links><link href="GUID-66C1493D-5B85-558A-9A39-454E6EBA307B.dita"><linktext>Signal Emulation on Symbian
+                Platform</linktext> </link> <link href="GUID-186B9876-2A08-5F23-BB49-49EC34C51507.dita"><linktext>Using Signals to Terminate Processes</linktext> </link> <link href="GUID-6CF8A41B-C2DD-5D57-A71D-6405CE08A06B.dita"><linktext>Using Signals to Handle Asynchronous
+                Events</linktext> </link> </related-links></concept>
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