filling arrays, avoid default init

[Thomas Kuehne]

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Lionello Lunesu schrieb am 2007-01-10:
>>> Uhm, sorry. That doesn't seem to prevent the initialization at all...
>>
>> Can you provide a code sampel?
>
> Well, Frank's code:
>
> TypeA[] ta = .... ; // big array with something
> TypeB[] tb = void;
> tb.length = ta.length; // (1)
> foreach( uint i, TypeA a; ta ){
>   tb[i] = ta[i].getB();
> }
>
> For unsized dynamic arrays (TypeB[]), =void does not prevent the 
> initialization when you change the length later.

It is working as advertised in
http://www.digitalmars.com/d/declaration.html (Void Initializations)
http://www.digitalamrs.com/d/arrays.html (Setting Dynamic Array Length)

The below code might help solve your problem with new'ing dynamic
arrays. (Windows most likely requires some "import" changes.)

# import internal.gc.gclinux;
# import internal.gc.gcbits;
# import internal.gc.gcx;
# import std.gc;
# 
# /**
#  * Void Initialization of a dynamic GC collected array
#  *
#  * Only use this template if you know what you are doing.
#  */
# template newVoidArray(T){
#    T[] newVoidArray(size_t elements){
#       return (cast(T*) (cast(GC)getGCHandle()).malloc(elements * T.sizeof))[0 .. elements];
#    }
# }
# 
# import std.stdio;
# typedef int X = 12_34_56_78;
# 
# void main(){
#    X[] a = new X[4];
#    X[] b = newVoidArray!(X)(4);
# 
#    writefln("a: %s", a);
#    writefln("b: %s", b);
# }

Thomas


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