Symbian3/SDK/Source/GUID-FC24C65C-0DCB-5E07-9A68-9001D34664DD.dita
author Dominic Pinkman <Dominic.Pinkman@Nokia.com>
Thu, 21 Jan 2010 18:18:20 +0000
changeset 0 89d6a7a84779
permissions -rw-r--r--
Initial contribution of Documentation_content according to Feature bug 1266 bug 1268 bug 1269 bug 1270 bug 1372 bug 1374 bug 1375 bug 1379 bug 1380 bug 1381 bug 1382 bug 1383 bug 1385

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<concept xml:lang="en" id="GUID-FC24C65C-0DCB-5E07-9A68-9001D34664DD"><title>OR_LEAVE MACRO</title><prolog><metadata><keywords/></metadata></prolog><conbody><p>The <xref href="GUID-7EB97E3A-90F5-3536-B7AC-F6F55023E2F3.dita"><apiname>OR_LEAVE</apiname></xref> macro is a convenient macro that allows the application developer to de-emphasize auxiliary error checking code in most cases. It is a postfix macro which implements <xref href="GUID-C197C9A7-EA05-3F24-9854-542E984C612D.dita#GUID-C197C9A7-EA05-3F24-9854-542E984C612D/GUID-80E99D34-F4A1-36EA-AD64-E14ACAEC99B0"><apiname>User::LeaveIfError</apiname></xref> on an integer return type. This means that there is less focus on the error handling code and makes the code easier to read. </p> <section><title>Need for OR_Leave Macro</title> <p>Motive behind using a <xref href="GUID-7EB97E3A-90F5-3536-B7AC-F6F55023E2F3.dita"><apiname>OR_LEAVE</apiname></xref> macro is that it should not return an integer value. It is intended for use as a postfix macro at the end of a statement. If OR_LEAVE was to return an integer value, it would encourage its use in the middle of expressions negating its intended purpose which is to reduce the focus on error checking code. </p> </section> <example><title>Defining OR_Leave Macro</title> <p>The OR_LEAVE macro is defined as a postfix operator as shown below: </p> <codeblock id="GUID-DDB19E73-7D96-5D06-8EF9-AEC1248E8644" xml:space="preserve">
        #define OR_LEAVE || ELeave
        inline void operator||(TInt aStatus, TLeave /*aTag*/)
            {
            User::LeaveIfError(aStatus);
            }
</codeblock> </example> <section><title>See Also</title> <p><xref href="GUID-B007634D-4D55-528A-8B85-6120C633AC8B.dita">EUser High Level Library Overview</xref>  </p> <p><xref href="GUID-D33EB877-CCCB-527B-8AFC-4A8385C55E78.dita">EUser High Level Library Tutorials</xref>  </p> </section> </conbody></concept>