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<concept xml:lang="en" id="GUID-9AC6774A-41E9-5298-8696-0A317A09E1E9"><title>Librt Overview</title><prolog><metadata><keywords/></metadata></prolog><conbody><p>Support for the Librt library on Symbian platform enables you to port Librt-based applications to Symbian platform quickly and easily. With knowledge of the Librt library you can also develop Librt-based applications on Symbian platform with minimal coding effort and without much knowledge of the native Symbian Utility C++ APIs. </p> <section><title>Librt library details</title> <p>The <filepath>librt.dll</filepath> provides the Librt functionality and your code must link to <filepath>librt.lib</filepath>. </p> <p> <b>Important:</b> Your application or library that uses the Librt library for the clock solutions must link to <filepath>librt.dll</filepath> prior to all other libraries in the link order. This is because both <filepath>libc.dll</filepath> and <filepath>librt.dll</filepath> provide similar clock interfaces but only the Librt library is modified to behave according to the LSB 3.1 specification. </p> </section> <section><title>Architecture</title> <p>The following image illustrates how the Librt library interacts with the components of the P.I.P.S. environment and also with Symbian platform: </p> <fig id="GUID-A29F100E-2726-501C-B141-BED577C50768"><title>

             The Librt library interacting with P.I.P.S. and Symbian platform

          </title> <image href="GUID-AE85751A-77CA-5C41-AF61-C9C9D776B066_d0e143159_href.png" placement="inline"/></fig> </section> <section><title>APIs</title> <p>The following table is a comprehensive list of Librt APIs as per the <xref scope="external" href="http://refspecs.linux-foundation.org/LSB_3.1.0/LSB-Core-generic/LSB-Core-generic/librt.html">LSB 3.1 specification</xref>: </p> <table id="GUID-843027AF-D604-5C35-9879-BE79121EE94D"><tgroup cols="1"><colspec colname="col0"/><thead><row><entry>API</entry> </row> </thead> <tbody><row><entry><p> <b>Shared Memory APIs</b>  </p> </entry> </row> <row><entry><p> <xref href="GUID-FF8FD54D-4CD3-3DC7-9A48-56043F26E5DD.dita"><apiname>shm_open()</apiname></xref>  </p> </entry> </row> <row><entry><p> <xref href="GUID-BF359599-0088-3F3E-BD80-B09C1F5DA380.dita"><apiname>shm_unlink()</apiname></xref>  </p> </entry> </row> <row><entry><p> <b>Clock APIs</b>  </p> </entry> </row> <row><entry><p> <xref href="GUID-D4D30F8D-82D9-3919-9711-DFEE78946DBE.dita"><apiname>clock_getcpuclockid()</apiname></xref>  </p> </entry> </row> <row><entry><p> <xref href="GUID-B27CD3ED-C472-3226-8B9F-C920E42FA918.dita"><apiname>clock_getres()</apiname></xref>  </p> </entry> </row> <row><entry><p> <xref href="GUID-2E94C94E-6D65-3B18-959D-60E6224E6C40.dita"><apiname>clock_gettime()</apiname></xref>  </p> </entry> </row> <row><entry><p> <xref href="GUID-24155E9E-530A-3D43-9B71-CF59153B33C9.dita"><apiname>clock_nanosleep()</apiname></xref>  </p> </entry> </row> <row><entry><p> <xref href="GUID-7FA65BF7-2F4F-3AA9-A52F-2CF655053AB7.dita"><apiname>clock_settime()</apiname></xref>  </p> </entry> </row> <row><entry><p> <b>Timer APIs</b>  </p> </entry> </row> <row><entry><p> <xref href="GUID-FD961A81-8D92-38D6-A2CE-F3215D5CCF38.dita"><apiname>timer_create()</apiname></xref>  </p> </entry> </row> <row><entry><p> <xref href="GUID-3C9E5145-5A20-3AE6-88C1-2D76BD68B2F0.dita"><apiname>timer_delete()</apiname></xref>  </p> </entry> </row> <row><entry><p> <xref href="GUID-C77553E5-ABEA-3253-B119-2F71C6241EAA.dita"><apiname>timer_getoverrun()</apiname></xref>  </p> </entry> </row> <row><entry><p> <xref href="GUID-F2DCFCBA-65B7-3184-B870-A63C6CF7EBA9.dita"><apiname>timer_gettime()</apiname></xref>  </p> </entry> </row> <row><entry><p> <xref href="GUID-5FE65EC4-4F2A-30C1-BA89-A92B1F9B1B2E.dita"><apiname>timer_settime</apiname></xref>  </p> </entry> </row> </tbody> </tgroup> </table> </section> <section><title>Using Librt</title> <p>The following tutorials describe some high-level usage scenarios of the Librt library functions: </p> <ul><li id="GUID-81EAC75C-5233-5440-95B9-E950AA7527BF"><p><xref href="GUID-8B37D53D-77E1-58C6-9A44-3376A450228B.dita">Shared Memory Tutorial</xref>  </p> </li> <li id="GUID-BA00DA3A-FD9A-52CA-AA40-F1CB0CC571A5"><p><xref href="GUID-66402932-5C44-556B-A7AC-1C2D245C8B05.dita">Clocks and Timers Tutorial</xref>  </p> </li> </ul> </section> </conbody></concept>