Pointers and offsets

Mike Parker via Digitalmars-d-learn digitalmars-d-learn at puremagic.com
Tue Jan 13 17:50:04 PST 2015


On 1/14/2015 10:17 AM, Bauss wrote:
> On Wednesday, 14 January 2015 at 01:16:54 UTC, Bauss wrote:
>> Is it possible to access a pointer by its offsets.
>> Ex. write a 32bit integer to a byte pointer at ex. offset 4.
>>
>> To give an example in C# you can do this:
>> fixed (byte* Packet = Buffer) // Buffer would be a byte array
>>
>> And then to set the value of a specific offset
>> *((TYPE*)(Packet + OFFSET))
>>
>> Where TYPE could be replaced by ex. uint and OFFSET by 4
>>
>> I tried to look here:
>> http://dlang.org/arrays.html
>>
>> But couldn't seem to find anything like it.
>
> Can't seem to edit OP so at:

The forum is a web interface to a newsgroup, which also has a mailing 
list interface. So no, no editing.

> *((TYPE*)(Packet + OFFSET))
>
> It should be:
> *((TYPE*)(Packet + OFFSET)) = VALUE;
>
> VALUE has to be of the same type as TYPE of course.

void main()
{
     ubyte[16] bytes;
     for( int i=0; i<4; ++i )
     {
         *(cast( int* )( bytes.ptr + (i*4))) = i;
     }

     import std.stdio : writeln;
     writeln( cast( int[] )bytes );
}


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