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<concept id="GUID-3314123F-205D-5E05-9041-DB9836B7812B" xml:lang="en"><title>File

Access Example: Accessing the File System Using P.I.P.S.</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>This example application shows, using a P.I.P.S. (P.I.P.S. Is POSIX on

the Symbian platform) program, the restrictions on file access that are imposed

by the Symbian platform Security model. </p>

<p>It shows that programs can access their own directories, but

cannot, without platform security capabilities not available to ordinary programs,

access the directories of other programs, or the system binary directory <filepath>sys/bin</filepath>. </p>

<p>This example defines an executable file with no platform security capabilities.

The program first creates its own secure directory that it can write to and

read from. It then attempts to use a file in a private directory of another

program, and then in <filepath>sys/bin</filepath>, and shows that these attempts

are denied. </p>

<section id="GUID-820F9B58-8877-414B-A18B-B591F6D67158"><title>Download</title> <p>Click

on the following link to download the example: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/zips/guid-2dae3cca-f112-4219-8f7c-6c48682d1f28.zip" scope="external">FileAccessExample.zip</xref></p><p>Click: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/guid-2dae3cca-f112-4219-8f7c-6c48682d1f28.html" scope="peer">browse</xref> to view the example code. </p> </section>

<section id="GUID-3EAFEC43-CFDA-4E3D-8ACD-E3AAE48BE97D"><title>Description</title> <p>The

following sections provide more information about the steps that the example

performs. </p> <p><b> Create a secure directory</b> </p> <p>The example creates

an empty secure directory for the program by using the <xref href="GUID-5EA72F64-E826-3B15-9468-902BD57F6AA7.dita"><apiname>mkdir()</apiname></xref> function. </p> <p>This

empty secure directory is created in <filepath>C:\private\E80000C9</filepath>,

as 0xE80000C9 is a unique identifier for the program (as specified by the

third UID in its project file). </p></section>

<section id="GUID-D9F306FF-D14E-4BCC-BAE6-55804F31CA0D"> <p><b>Write and read

a file in the private directory </b> </p> <p>The example writes and reads

a file in the secure directory using the <xref href="GUID-64886CC6-072F-3542-855A-5D733FC761E8.dita"><apiname>fopen()</apiname></xref> and other

file stream functions. </p> <p><b> Write and read a file in the private directory

of another program </b> </p> <p>The example attempts to write and read a file

in the secure directory of another program. </p> <p>The <xref href="GUID-64886CC6-072F-3542-855A-5D733FC761E8.dita"><apiname>fopen()</apiname></xref> function

is expected to return <codeph>NULL</codeph>, indicating that access is not

possible, as the program has insufficient platform security capabilities. </p><p><b> Write

and read a file in the sys/bin directory</b> </p> <p>The example attempts

to write and read a file in the system's <filepath>sys/bin</filepath> directory,

where program binaries are stored. </p> <p>Again, the <xref href="GUID-64886CC6-072F-3542-855A-5D733FC761E8.dita"><apiname>fopen()</apiname></xref> function

is expected to return <codeph>NULL</codeph>, indicating that access is not

possible, as the program has insufficient platform security capabilities. </p> </section>

<section id="GUID-EB4F71F2-D55D-43C5-B55F-F211D170056F"><title>Related APIs</title><p><xref href="GUID-5EA72F64-E826-3B15-9468-902BD57F6AA7.dita"><apiname>mkdir()</apiname></xref></p><p><xref href="GUID-64886CC6-072F-3542-855A-5D733FC761E8.dita"><apiname>fopen()</apiname></xref></p></section>

<section id="GUID-81AA0C7F-5D43-4EFB-9DD0-4A8A79922576"><title>Build</title> <p>The <xref href="GUID-3100800B-B2F7-50EF-BD4C-3C345ECCB2A5.dita">Symbian build process</xref> describes

how to build this example application. </p> <p>The example builds an executable

called <filepath>fileaccessexample.exe</filepath> in the standard locations. </p> <p>To

run the example, start <filepath>fileaccessexample.exe</filepath> from the

file system or from your IDE. After launching the executable, depending on

the emulator you are using, you may need to navigate away from the application

launcher or shell screen to view the console. </p> </section>