Sorry for the question. I am a n00b to D. I tried to compile the following code from Alexandrescu's book:

import std.stdio;
class A {
  int x = 42;
}

unittest {
  auto a1 = new A;
  assert (a1.x == 42);
  auto a2 = a1;
  a2.x = 100;
  assert (a1.x == 100);
}

at the command line:

/d$ dmd c.d
/usr/lib/i386-linux-gnu/libphobos2.a(dmain2_473_1a5.o): In function `main':
src/rt/dmain2.d:(.text.main+0x4): undefined reference to `_Dmain'
/usr/lib/i386-linux-gnu/libphobos2.a(deh2_453_525.o): In function `_D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable':
src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x4): undefined reference to `_deh_beg'
src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0xc): undefined reference to `_deh_beg'
src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x12): undefined reference to `_deh_end'

...

plus much more encrypted Klingon.

Help?

On Saturday, 23 March 2013 at 21:04:25 UTC, Patrick Tinkham wrote:
> Sorry for the question. I am a n00b to D. I tried to compile the following code from Alexandrescu's book:
>
> import std.stdio;
> class A {
>   int x = 42;
> }
>
> unittest {
>   auto a1 = new A;
>   assert (a1.x == 42);
>   auto a2 = a1;
>   a2.x = 100;
>   assert (a1.x == 100);
> }
>
> at the command line:
>
> /d$ dmd c.d
> /usr/lib/i386-linux-gnu/libphobos2.a(dmain2_473_1a5.o): In function `main':
> src/rt/dmain2.d:(.text.main+0x4): undefined reference to `_Dmain'
> /usr/lib/i386-linux-gnu/libphobos2.a(deh2_453_525.o): In function `_D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable':
> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x4): undefined reference to `_deh_beg'
> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0xc): undefined reference to `_deh_beg'
> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x12): undefined reference to `_deh_end'
>
> ...
>
> plus much more encrypted Klingon.
>
> Help?

You need a main function:

import std.stdio;
class A {
  int x = 42;
}

unittest {
  auto a1 = new A;
  assert (a1.x == 42);
  auto a2 = a1;
  a2.x = 100;
  assert (a1.x == 100);
}

void main() { }

On Saturday, March 23, 2013 22:04:23 Patrick Tinkham wrote:
> Sorry for the question. I am a n00b to D. I tried to compile the following code from Alexandrescu's book:
> 
> import std.stdio;
> class A {
>    int x = 42;
> }
> 
> unittest {
>    auto a1 = new A;
>    assert (a1.x == 42);
>    auto a2 = a1;
>    a2.x = 100;
>    assert (a1.x == 100);
> }
> 
> at the command line:
> 
> /d$ dmd c.d
> /usr/lib/i386-linux-gnu/libphobos2.a(dmain2_473_1a5.o): In
> function `main':
> src/rt/dmain2.d:(.text.main+0x4): undefined reference to `_Dmain'
> /usr/lib/i386-linux-gnu/libphobos2.a(deh2_453_525.o): In function
> `_D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable':
> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x4):
> undefined reference to `_deh_beg'
> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0xc):
> undefined reference to `_deh_beg'
> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x12)
> : undefined reference to `_deh_end'
> 
> ...
> 
> plus much more encrypted Klingon.
> 
> Help?

You have to have a main function. Either add one, or use rdmd --main to compile (instead of dmd) so that a stub main is added for you. In either case, you need -unittest to enable the unit tests.

Also, questions on learning D should go to the D.Learn newsgroup, whereas this is the D newsgroup, which is for general discussion on the language itself.

- Jonathan M Davis

On Saturday, 23 March 2013 at 21:04:25 UTC, Patrick Tinkham wrote:
> /d$ dmd c.d
> /usr/lib/i386-linux-gnu/libphobos2.a(dmain2_473_1a5.o): In function `main':
> src/rt/dmain2.d:(.text.main+0x4): undefined reference to `_Dmain'
...
> plus much more encrypted Klingon.
>
> Help?

Fixed: http://dpaste.1azy.net/282d8d3f

On Saturday, 23 March 2013 at 21:08:39 UTC, Namespace wrote:
> On Saturday, 23 March 2013 at 21:04:25 UTC, Patrick Tinkham wrote:
>> Sorry for the question. I am a n00b to D. I tried to compile the following code from Alexandrescu's book:
>>
>> import std.stdio;
>> class A {
>>  int x = 42;
>> }
>>
>> unittest {
>>  auto a1 = new A;
>>  assert (a1.x == 42);
>>  auto a2 = a1;
>>  a2.x = 100;
>>  assert (a1.x == 100);
>> }
>>
>> at the command line:
>>
>> /d$ dmd c.d
>> /usr/lib/i386-linux-gnu/libphobos2.a(dmain2_473_1a5.o): In function `main':
>> src/rt/dmain2.d:(.text.main+0x4): undefined reference to `_Dmain'
>> /usr/lib/i386-linux-gnu/libphobos2.a(deh2_453_525.o): In function `_D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable':
>> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x4): undefined reference to `_deh_beg'
>> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0xc): undefined reference to `_deh_beg'
>> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x12): undefined reference to `_deh_end'
>>
>> ...
>>
>> plus much more encrypted Klingon.
>>
>> Help?
>
> You need a main function:
>
> import std.stdio;
> class A {
>   int x = 42;
> }
>
> unittest {
>   auto a1 = new A;
>   assert (a1.x == 42);
>   auto a2 = a1;
>   a2.x = 100;
>   assert (a1.x == 100);
> }
>
> void main() { }

Thank you!!! (I guess I'm just accustomed to stand-alone classes in Java...)

On Saturday, 23 March 2013 at 21:12:25 UTC, Patrick Tinkham wrote:
> On Saturday, 23 March 2013 at 21:08:39 UTC, Namespace wrote:
>> On Saturday, 23 March 2013 at 21:04:25 UTC, Patrick Tinkham wrote:
>>> Sorry for the question. I am a n00b to D. I tried to compile the following code from Alexandrescu's book:
>>>
>>> import std.stdio;
>>> class A {
>>> int x = 42;
>>> }
>>>
>>> unittest {
>>> auto a1 = new A;
>>> assert (a1.x == 42);
>>> auto a2 = a1;
>>> a2.x = 100;
>>> assert (a1.x == 100);
>>> }
>>>
>>> at the command line:j
>>>
>>> /d$ dmd c.d
>>> /usr/lib/i386-linux-gnu/libphobos2.a(dmain2_473_1a5.o): In function `main':
>>> src/rt/dmain2.d:(.text.main+0x4): undefined reference to `_Dmain'
>>> /usr/lib/i386-linux-gnu/libphobos2.a(deh2_453_525.o): In function `_D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable':
>>> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x4): undefined reference to `_deh_beg'
>>> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0xc): undefined reference to `_deh_beg'
>>> src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh29FuncTable+0x12): undefined reference to `_deh_end'
>>>
>>> ...
>>>
>>> plus much more encrypted Klingon.
>>>
>>> Help?
>>
>> You need a main function:
>>
>> import std.stdio;
>> class A {
>>  int x = 42;
>> }
>>
>> unittest {
>>  auto a1 = new A;
>>  assert (a1.x == 42);
>>  auto a2 = a1;
>>  a2.x = 100;
>>  assert (a1.x == 100);
>> }
>>
>> void main() { }
>
> Thank you!!! (I guess I'm just accustomed to stand-alone classes in Java...)

dmd has a flag - - main that auto generates a blank main function to prevent linker errors.

"John Colvin" <john.loughran.colvin@gmail.com> wrote in message news:czgwwpslprqslewmsjnq@forum.dlang.org...
>
> dmd has a flag - - main that auto generates a blank main function to prevent linker errors.

I don't think this is in the released version yet.

On Sunday, March 24, 2013 16:59:51 Daniel Murphy wrote:
> "John Colvin" <john.loughran.colvin@gmail.com> wrote in message news:czgwwpslprqslewmsjnq@forum.dlang.org...
> 
> > dmd has a flag - - main that auto generates a blank main function to prevent linker errors.
> 
> I don't think this is in the released version yet.

It _has_ been in rdmd for quite some time though.

- Jonathan M Davis