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<concept id="GUID-063020E5-51C0-45C3-8B8B-015385FA0928" xml:lang="en"><title>Redirect

Printf Example</title><shortdesc>Redirect standard I/O to a file</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>This example illustrates how to redirect standard I/O to a file. The <codeph>libc</codeph> library

provides <xref href="GUID-6A17B64B-44DC-33F0-B18A-25004500C831.dita"><apiname>freopen()</apiname></xref> API to redirect all standard IOs (namely

- stderr, stdin or stdout). Application first prints launching information

at the console and then opens one file to redirect standard output using <xref href="GUID-6A17B64B-44DC-33F0-B18A-25004500C831.dita"><apiname>freopen()</apiname></xref>.

Calling <xref href="GUID-6A17B64B-44DC-33F0-B18A-25004500C831.dita"><apiname>freopen()</apiname></xref> once more, the user can change the filename

during execution. This helps to redirect application <xref href="GUID-919E1C29-029A-38E2-B844-141A6E02ADA2.dita"><apiname>printf()</apiname></xref> messages

into a log file. </p>

<section id="GUID-026FD8D6-6C4A-5958-B289-775D4AE1E756-GENID-1-10-1-12-1-1-5-1-3-1-11-1-16-1-3-2"><title>Download</title> <p>Click

on the following link to download the example: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/zips/guid-b83a4952-b5e5-4ef5-a1c9-ee48705964a1.zip" scope="external">redirectprintf.zip</xref></p><p>Click: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/guid-b83a4952-b5e5-4ef5-a1c9-ee48705964a1.html" scope="peer">browse</xref> to view the example code. </p> </section>

<section id="GUID-7E7C4564-B10E-41F9-8A9D-D8A6C5E9C51C-GENID-1-10-1-12-1-1-5-1-3-1-11-1-16-1-3-3"><title>Design and

Implementation</title> <p>The following sections provide information about

the implementation of the example. </p> <p><b>Capabilities</b> </p>The program

capabilities are defined in <filepath>redirectprintf.mmp</filepath> : <codeph>CAPABILITY

NONE</codeph>. </section>

<section id="GUID-67A72761-1D92-46D1-B1C9-7455978BDE4E-GENID-1-10-1-12-1-1-5-1-3-1-11-1-16-1-3-4"><title>Building and

Using</title> To build the example application, go to the redirectprintf\group

directory and build the application.  The definition for the whole application

can be found in the bld.inf file in the group subdirectory of the applications

main directory.<p>The application is simple console based application. It

has its own default icon and can be launched from the UI both

in the emulator and in the device.  The application can be launched by: Executing

redirectprintf from eshell.  Clicking default icon with display text redirectprintf

within the install folder launcher application. </p> </section>

</conbody></concept>