Compiling the following with DMD and executing the program yields an segmentation fault when accessing the public field 'the_date.year' of another public field 'birth':


import std.c.stdio;
import std.c.stdlib;
import std.string;
import std.date;

public class MyDate {
  public:
  Date   the_date;       // only the field 'year' is relevant

  this(){ the_date.year = 1901; }
};

public class Author {
   public:
   MyDate   birth;
};

int main(char[][] args)
{
   Author author = new Author();
   MyDate mydate = new MyDate();

   printf("(1) accessing: mydate.the_date.year = %i\n", mydate.the_date.year);
   printf("(2) accessing: author.birth.the_date.year = \n");
   printf("%i\n",     author.birth.the_date.year);

   printf("Ok.\n");

   return 0;
}

To my understanding, this access is legal; if not, then the compiler should
refuse it.
Enlighten me if I am doing something wrong here (I am new to D).

Here is the screen output sniplet: -------------------------------------
phobos:~/Lang/D/Toy/segfault> make test
/home/oli/Projects/D/DMD/dmd/bin/dmd  -c -oftest_date.o test_date.d
/home/oli/Projects/D/DMD/dmd/bin/dmd -oftest_date.exe test_date.o
gcc test_date.o -o test_date.exe -m32 -lphobos -lpthread -lm

phobos:~/Lang/D/Toy/segfault> ./test_date.exe
(1) accessing: mydate.the_date.year = 1901
(2) accessing: author.birth.the_date.year =
Segmentation fault
-------------------------------------------------------------------------
Running test_date.d interpreted has the same effect (abort on (2)).

Versions:
dmd: Digital Mars D Compiler v1.0
gcc: gcc (GCC) 4.0.2 20050901 (prerelease) (SUSE Linux)
platform: PC SuSE Linux 10.0 (64 bit)

** Computers will always make mistakes, but will do so much faster tomorrow. ** ------------------------------------------------- <omoeller@verify-it.de>

the Date is a struct and is of value type. (1) is OK so.
The MyDate is a class and is a reference type. This is why (2) fails.
You did not initialize Author.birth.

> public class Author {
>    public:
>    MyDate   birth;
this(){
  birth=new MyDate();
}
> };


Oliver Moeller schrieb:
> Compiling the following with DMD and executing the program yields an segmentation fault when accessing the public field 'the_date.year' of another public field 'birth':
> 
> 
> import std.c.stdio;
> import std.c.stdlib;
> import std.string;
> import std.date;
> 
> public class MyDate {
>   public:
>   Date   the_date;       // only the field 'year' is relevant
> 
>   this(){ the_date.year = 1901; }
> };
> 
> public class Author {
>    public:
>    MyDate   birth;
> };
> 
> int main(char[][] args)
> {
>    Author author = new Author();
>    MyDate mydate = new MyDate();
> 
>    printf("(1) accessing: mydate.the_date.year = %i\n", mydate.the_date.year);
>    printf("(2) accessing: author.birth.the_date.year = \n");
>    printf("%i\n",     author.birth.the_date.year);
> 
>    printf("Ok.\n");
> 
>    return 0;
> }
> 
> To my understanding, this access is legal; if not, then the compiler should
> refuse it.
> Enlighten me if I am doing something wrong here (I am new to D).
> 
> Here is the screen output sniplet: -------------------------------------
> phobos:~/Lang/D/Toy/segfault> make test
> /home/oli/Projects/D/DMD/dmd/bin/dmd  -c -oftest_date.o test_date.d
> /home/oli/Projects/D/DMD/dmd/bin/dmd -oftest_date.exe test_date.o
> gcc test_date.o -o test_date.exe -m32 -lphobos -lpthread -lm
> 
> phobos:~/Lang/D/Toy/segfault> ./test_date.exe
> (1) accessing: mydate.the_date.year = 1901
> (2) accessing: author.birth.the_date.year =
> Segmentation fault
> -------------------------------------------------------------------------
> Running test_date.d interpreted has the same effect (abort on (2)).
> 
> Versions:
> dmd: Digital Mars D Compiler v1.0
> gcc: gcc (GCC) 4.0.2 20050901 (prerelease) (SUSE Linux)
> platform: PC SuSE Linux 10.0 (64 bit)
> 
> ** Computers will always make mistakes, but will do so much faster tomorrow. ** ------------------------------------------------- <omoeller@verify-it.de>