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<concept xml:lang="en" id="GUID-685CF352-372F-5393-97AF-1FA17DC57BA8"><title>Constructing Descriptor Arrays</title><shortdesc>Descriptor arrays provide normal array operations for inserting, appending, deleting, and accessing elements. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody><section><title>Procedure</title> <p>Follow the steps listed below to construct descriptor arrays: </p> <ol id="GUID-4957F727-EC6C-5DFF-B970-44DD0AB5E69C"><li id="GUID-69B3273C-1552-5B9C-816D-1398BFF49A6B"><p>Construct a set of descriptors. </p> <p>The following code fragments illustrate how to construct a <xref href="GUID-29384669-FFCE-38FC-A005-61163D99401D.dita"><apiname>CDesCArrayFlat</apiname></xref> and a <xref href="GUID-FC3F3E4A-C86C-3DDB-B851-538BF20D5B27.dita"><apiname>CPtrCArray</apiname></xref>. Both array types can accept any type of descriptor as source when adding a new array element. </p> <codeblock id="GUID-AEE8ABB8-CCCE-5263-8EA4-AD2D8898F4D4" xml:space="preserve">_LIT( KText1,"abcdefg" );

_LIT( KText2,"hijk" );

_LIT( KText3,"lmnopqr" );

_LIT( KText4,"stuvwxyz" );

...

TBufC<8> buffer1( KText1 );  // a non-modifiable buffer descriptor

TBuf<8>  buffer2( Ktext2 );  // a modifiable buffer descriptor

...

TPtrC  ptr1( Ktext3 );       // a non-modifiable pointer descriptor

TPtr   ptr2;                 // a modifiable pointer descriptor 

ptr2 = buffer1.Des();        // pointing to the data in buffer1

...

HBufC* heapbuff = HBufC::NewL( 8 );  // a heap descriptor

*heapbuff = KText4;</codeblock> <p> <b>Note:</b> Constructing and using a <xref href="GUID-1B44227C-6F11-3A51-BE2C-8780319C6F72.dita"><apiname>CDesCArraySeg</apiname></xref> is same as using <xref href="GUID-29384669-FFCE-38FC-A005-61163D99401D.dita"><apiname>CDesCArrayFlat</apiname></xref>. </p> </li> <li id="GUID-8A1E403F-FBA4-5A60-AAC4-7296BA7B160F"><p>Add the five descriptors to <xref href="GUID-29384669-FFCE-38FC-A005-61163D99401D.dita"><apiname>CDesCArrayFlat</apiname></xref> as shown in the following code. </p> <codeblock id="GUID-6DE21030-1887-53D8-8D04-B9DB0F69F647" xml:space="preserve">CDesCArrayFlat* descarray;

...

descarray = new( ELeave ) CDesCArrayFlat( 5 );

...

descarray->AppendL( buffer1 );

descarray->AppendL( buffer2 );

descarray->AppendL( ptr1 );

descarray->AppendL( ptr2 );

descarray->AppendL( *heapbuff );

...

TInt len = descarray->MdcaPoint( 2 ).Length();  // information about

                                                // the third element

...</codeblock> </li> <li id="GUID-EE266B93-2899-5D35-A0BF-569694574D5C"><p>Add the five descriptors to <xref href="GUID-FC3F3E4A-C86C-3DDB-B851-538BF20D5B27.dita"><apiname>CPtrCArray</apiname></xref> as shown in the following code. </p> <codeblock id="GUID-90A51320-7B9E-5DAD-A041-77FD6B2C3A37" xml:space="preserve">CPtrCArray* ptrcarray;

...

ptrcarray = new( ELeave ) CPtrCArray( 5 );

...

ptrcarray->AppendL( buffer1 );

ptrcarray->AppendL( buffer2 );

ptrcarray->AppendL( ptr1 );

ptrcarray->AppendL( ptr2 );

ptrcarray->AppendL( *heapbuff );

...

TInt len = ptrcarray->MdcaPoint( 2 ).Length();  // information about

                                                // the third element