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  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-44F4089F-7184-5F73-A01E-E0F639D32EA1" xml:lang="en"><title>System
Wide Error Codes Overview</title><shortdesc>This is an overview document of error codes used system APIs. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<section id="GUID-6B6D8FFA-DF27-44D5-AEBF-5CCC81D4C39F"><title>Purpose</title> <p>Provides a core set of error codes that
may be returned by System APIs. They are defined in e32err.h. </p> </section>
<section id="GUID-B103B96A-B168-4F3C-821B-AF56D0E35643"><title>Description</title> <p>These error codes are used by System
APIs to indicate common mathematical, file, communications, and client/server
errors. These error codes are intended to be generic to reflect the fact that
many error conditions occur for similar reasons in nearly all software components.
The errors may also be returned by non-System APIs where appropriate. APIs
may also use additional error codes where the core set is not sufficient. </p> <p>Error
codes are returned to clients in three circumstances: </p> <ul>
<li id="GUID-ED9D2507-15E4-528B-AF04-3D0CC21F758D"><p>as a simple <xref href="GUID-7A2A43EC-6125-3BFE-834B-23C37F7B40D5.dita"><apiname>TInt</apiname></xref> return
value from a synchronous function </p> </li>
<li id="GUID-50CC41C2-6EA7-5DCB-A4B8-5092A15A1C53"><p>as a leave code from
a leaving function, which can be caught in a trap harness </p> </li>
<li id="GUID-2D401685-8851-574B-A672-47DFAF9F3C52"><p>in a request status,
when an asynchronous request function completes </p> </li>
</ul> <p>The complete list can be found at e32err.h. This not only describes
the symbols used in C++ code, but also the numerical values that those symbols
represent. </p> <p>In the code itself, the core list is defined in the header
file <filepath>e32err.h</filepath>. </p> </section>
<section id="GUID-9B23BFC3-25DB-4578-ABB1-AF4E38431967"><title>See also</title> <p><xref href="GUID-1294F540-FDA7-5050-BAFB-3C9888491B98.dita">Asynchronous
Services Overview</xref>  </p> <p><xref href="GUID-E5A83EF3-948B-5729-A2CD-3644E803520B.dita">Cleanup
Support Overview</xref>  </p> </section>
</conbody></concept>