7 Nokia Corporation - initial contribution. |
7 Nokia Corporation - initial contribution. |
8 Contributors: |
8 Contributors: |
9 --> |
9 --> |
10 <!DOCTYPE concept |
10 <!DOCTYPE concept |
11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
12 <concept id="GUID-772DFFA1-4BBC-516F-909D-47CB773760F5" xml:lang="en"><title>Packages |
12 <concept id="GUID-772DFFA1-4BBC-516F-909D-47CB773760F5" xml:lang="en"><title>Packages as type-safe descriptors</title><shortdesc>Describes the package function to transfer data in correct |
13 as type-safe descriptors</title><shortdesc>Describes the package function to transfer data in correct structure. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
13 structure. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
14 <p>Descriptors are often used as the basis of data transfer within Symbian |
14 <p>Descriptors are often used as the basis of data transfer within |
15 platform. For example, inter-thread data transfer is specified in terms of |
15 Symbian platform. For example, inter-thread data transfer is specified |
16 transferring data from a descriptor valid in the context of one thread, to |
16 in terms of transferring data from a descriptor valid in the context |
17 a descriptor valid in the context of another.</p> |
17 of one thread, to a descriptor valid in the context of another.</p> |
18 <p>Data to be transferred almost always has a well defined structure and it |
18 <p>Data to be transferred almost always has a well defined structure |
19 is important that the receiver of the data has some guarantee that the correct |
19 and it is important that the receiver of the data has some guarantee |
20 structure has been passed. This is type safety.</p> |
20 that the correct structure has been passed. This is type safety.</p> |
21 <p>A package <i>is</i> a descriptor and also acts as a wrapper around it. |
21 <p>A package <i>is</i> a descriptor and also acts as a wrapper around |
22 It allows objects and data structures to be represented by descriptors in |
22 it. It allows objects and data structures to be represented by descriptors |
23 a type safe way. Objects are either contained within a modifiable buffer descriptor |
23 in a type safe way. Objects are either contained within a modifiable |
24 or are represented by pointer descriptors.</p> |
24 buffer descriptor or are represented by pointer descriptors.</p> |
25 <p>A package class is templated, the template parameter being the type of |
25 <p>A package class is templated, the template parameter being the |
26 the object represented. The use of a template provides the required type safety.</p> |
26 type of the object represented. The use of a template provides the |
|
27 required type safety.</p> |
27 </conbody><related-links> |
28 </conbody><related-links> |
28 <link> |
29 <link href="GUID-79BAF19D-F003-5468-9C01-6E918B06C36D.dita"> |
29 <desc><xref href="GUID-79BAF19D-F003-5468-9C01-6E918B06C36D.dita">Descriptor concepts</xref></desc> |
30 <linktext>Descriptor concepts</linktext></link> |
30 </link> |
|
31 </related-links></concept> |
31 </related-links></concept> |