read fails with both uint and ulong on 64bit platform:

 Error: template std.bitmanip.read cannot deduce function from argument types !(ulong)(ubyte[8]), candidates are:
C:\ldc2-1.9.0-windows-x64\bin\..\import\std\bitmanip.d(3213,3):        std.bitmanip.read(T, Endian endianness = Endian.bigEndian, R)(ref R range) if (canSwapEndianness!T && isInputRange!R && is(ElementType!R : const(ubyte)))

code:

		import digestx.fnv;
		import std.bitmanip : read;
		FNV64 fnv64;
		fnv64.start();
		fnv64.put(cast(ubyte[])word);
		ubyte[8] arr = fnv64.finish();
		auto h = arr.read!ulong;
		return cast(uint)h;

On Wednesday, May 23, 2018 19:36:07 Dr.No via Digitalmars-d-learn wrote:
> read fails with both uint and ulong on 64bit platform:
>
>   Error: template std.bitmanip.read cannot deduce function from
> argument types !(ulong)(ubyte[8]), candidates are:
> C:\ldc2-1.9.0-windows-x64\bin\..\import\std\bitmanip.d(3213,3):
>       std.bitmanip.read(T, Endian endianness = Endian.bigEndian,
> R)(ref R range) if (canSwapEndianness!T && isInputRange!R &&
> is(ElementType!R : const(ubyte)))
>
> code:
>
>       import digestx.fnv;
>       import std.bitmanip : read;
>       FNV64 fnv64;
>       fnv64.start();
>       fnv64.put(cast(ubyte[])word);
>       ubyte[8] arr = fnv64.finish();
>       auto h = arr.read!ulong;
>       return cast(uint)h;

As the template constraint in the error message says, read requires an input range. Static arrays are not input ranges. You need to give it a dynamic array - and since read takes its argument by reference, you can't simply slice the static array and pass it. You need a variable that's a dynamic array.

- Jonathan M Davis

On Wednesday, 23 May 2018 at 19:49:27 UTC, Jonathan M Davis wrote:
> On Wednesday, May 23, 2018 19:36:07 Dr.No via Digitalmars-d-learn wrote:
>>       [...]
>
> As the template constraint in the error message says, read requires an input range. Static arrays are not input ranges. You need to give it a dynamic array - and since read takes its argument by reference, you can't simply slice the static array and pass it. You need a variable that's a dynamic array.
>
> - Jonathan M Davis

sorry, the error message wasn't clear to me. When I use dynamic arrays I get:

slice of static array temporary returned by fnv64.finish() assigned to longer lived variable arr

What should use instead of?

On 5/23/18 3:53 PM, Dr.No wrote:
> On Wednesday, 23 May 2018 at 19:49:27 UTC, Jonathan M Davis wrote:
>> On Wednesday, May 23, 2018 19:36:07 Dr.No via Digitalmars-d-learn wrote:
>>>       [...]
>>
>> As the template constraint in the error message says, read requires an input range. Static arrays are not input ranges. You need to give it a dynamic array - and since read takes its argument by reference, you can't simply slice the static array and pass it. You need a variable that's a dynamic array.
>>
>> - Jonathan M Davis
> 
> sorry, the error message wasn't clear to me. When I use dynamic arrays I get:
> 
> slice of static array temporary returned by fnv64.finish() assigned to longer lived variable arr
> 
> What should use instead of?

I'm guessing you wrote:

ubyte[] arr = fnv64.finish();

??

You want:

auto arrtmp = fnv64.finish();
auto arr = arrtmp[];

Basically, what you were doing is allocating some stack space to hold a static array that immediately goes out of scope, and then storing a slice to it.

-Steve