When I attempt to compile my code I get the same linker error with both dmd and ldc2. I know where the problematic code is, as I don't get the error when I comment out lines 102 through 107, but I don't understand why it's bad. I must have some misconceptions about how templates work? Is there any way to get more descriptive errors out of the compiler if this sort of thing happens again in the future?

Here's the code:

    http://pastebin.com/kGUPVa59

Here's the problematic lines:

    final streamint writestring(in char[] str){
        return this.writebuffer!char(str.ptr, str.length);
    }
    final streamint writestring(in string str){
        return this.writebuffer!char(str.ptr, str.length);
    }

And the linker error:

    Undefined symbols for architecture x86_64:
      "_D6stream6Stream19__T11writebufferTaZ11writebufferMFxPaxlZl", referenced from:
          _D6stream6Stream11writestringMFxAaZl in stream.o
          _D6stream6Stream11writestringMFxAyaZl in stream.o
    ld: symbol(s) not found for architecture x86_64
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    --- errorlevel 1

On Wednesday, 28 October 2015 at 11:11:01 UTC, pineapple wrote:
> When I attempt to compile my code I get the same linker error with both dmd and ldc2. I know where the problematic code is, as I don't get the error when I comment out lines 102 through 107, but I don't understand why it's bad. I must have some misconceptions about how templates work? Is there any way to get more descriptive errors out of the compiler if this sort of thing happens again in the future?
>
> Here's the code:
>
>     http://pastebin.com/kGUPVa59
>
> Here's the problematic lines:
>
>     final streamint writestring(in char[] str){
>         return this.writebuffer!char(str.ptr, str.length);
>     }
>     final streamint writestring(in string str){
>         return this.writebuffer!char(str.ptr, str.length);
>     }
>
> And the linker error:
>
>     Undefined symbols for architecture x86_64:
>       "_D6stream6Stream19__T11writebufferTaZ11writebufferMFxPaxlZl", referenced from:
>           _D6stream6Stream11writestringMFxAaZl in stream.o
>           _D6stream6Stream11writestringMFxAyaZl in stream.o
>     ld: symbol(s) not found for architecture x86_64
>     clang: error: linker command failed with exit code 1 (use -v to see invocation)
>     --- errorlevel 1

The "writebuffer" is defined to take an array as parameter. Yet, you are passing a pointer and a length to it. Instead, pass the parameter "str" to it directly. Also, you do not have to put "!char" to there. Compiler will solve it out by itself.

On Wednesday, 28 October 2015 at 11:40:14 UTC, tcak wrote:
> The "writebuffer" is defined to take an array as parameter. Yet, you are passing a pointer and a length to it. Instead, pass the parameter "str" to it directly. Also, you do not have to put "!char" to there. Compiler will solve it out by itself.

There's also a writebuffer method in the interface with this signature, though:

    streamint writebuffer(T)(in T* buffer, in streamint count);

And regardless, changing the problematic code to this doesn't address the linker error:

    final streamint writestring(in char[] str){
        return this.writebuffer(str);
    }
    final streamint writestring(in string str){
        return this.writebuffer(str);
    }

On Wednesday, 28 October 2015 at 11:48:27 UTC, pineapple wrote:
> There's also a writebuffer method in the interface with this signature, though:
>
>     streamint writebuffer(T)(in T* buffer, in streamint count);

Interface can't have templated virtual instance methods.

On Wednesday, 28 October 2015 at 11:48:27 UTC, pineapple wrote:
> On Wednesday, 28 October 2015 at 11:40:14 UTC, tcak wrote:
>> The "writebuffer" is defined to take an array as parameter. Yet, you are passing a pointer and a length to it. Instead, pass the parameter "str" to it directly. Also, you do not have to put "!char" to there. Compiler will solve it out by itself.
>
> There's also a writebuffer method in the interface with this signature, though:
>
>     streamint writebuffer(T)(in T* buffer, in streamint count);
>
> And regardless, changing the problematic code to this doesn't address the linker error:
>
>     final streamint writestring(in char[] str){
>         return this.writebuffer(str);
>     }
>     final streamint writestring(in string str){
>         return this.writebuffer(str);
>     }

This still doesn't solve everything, but the first thing to do is to define a method for those in the interface as well.

streamint writebuffer(T)(in T* buffer, in streamint count)
streamint writebuffer(T)(in T* buffer, in streamint count, bool dynamic);

On Wednesday, 28 October 2015 at 12:06:14 UTC, Kagamin wrote:
> On Wednesday, 28 October 2015 at 11:48:27 UTC, pineapple wrote:
>> There's also a writebuffer method in the interface with this signature, though:
>>
>>     streamint writebuffer(T)(in T* buffer, in streamint count);
>
> Interface can't have templated virtual instance methods.

What might be my options for restructuring the code to avoid this, ideally without sacrificing functionality? I imagine I must be able to use a void pointer instead? But that's just ugly.

Maybe I could do something like this?

    streamint writebuffer(in void* buffer, in streamint count);
    final streamint writebuffer(T){in T* buffer, in streamint count){
        return this.writebuffer(cast(void*) buffer, sizeof(*buffer) * count);
    }

    streamint writebuffer(in ubyte[] buffer);
    final streamint writebuffer(T)(in T* buffer, in streamint count){
        return this.writebuffer(cast(ubyte[])buffer[0..count]);
    }