(I must be missing something here; this is such a fundamental operation and I can't find a bug report on it.)

I've been under the impression that struct members would always be initialized. Having seen D an init-happy language compared to C and C++, that's what I would have expected. :)

Shouldn't the members of s be int.init and double.init below?

struct S
{
    int i;
    double d;
}

void main()
{
    S s;
}

They are not; at least for dmd versions from 2.034 to 2.037.

Also, leaving out some of the initializers do not init the corresponding members either:

    S s = { 42 };

There, s.d is not double.init.

And static initializers don't help either:

struct S
{
    int i     = 1;
    double d  = 2.3;
}

Again, s.d is not initialized:

    S s = { 42 };

Is the above expected? (Not by me... :) )

Ali

This prints 42 0.000000 with the latest dmd2 and 42 nan with an older dmd1. It can be a bug:

import std.c.stdio: printf;

struct S {
    int i;
    double d;
}

void main() {
    S s = { 42 };
    printf("%d %f\n", s.i, s.d);
}

Bye,
bearophile

Ali Cehreli Wrote:

> (I must be missing something here

Yes I am! :)

> I've been under the impression that struct members would always be initialized. Having seen D an init-happy language compared to C and C++, that's what I would have expected. :)

I still think that it should be the default behavior unless no-initialization was specifically requested, like the case for uninitialized arrays.

> struct S
> {
>     int i;
>     double d;
> }
[...]
> Also, leaving out some of the initializers do not init the corresponding members either:
> 
>     S s = { 42 };
> 
> There, s.d is not double.init.

The spec says "Members not specified in the initializer list are default initialized" for *static* objects. So this works:

    static S s = { 42 };
    dout.writefln(s.d);       // prints nan

This check fails though:

    assert(s.d == double.nan);

and it is probably not meant to work anyway; because I see that the spec at

    http://www.digitalmars.com/d/2.0/float.html

has this to say (probably recently modified):

   x == x → true 	not valid if x is a NaN

> struct S
> {
>     int i     = 1;
>     double d  = 2.3;
> }
> 

>     S s = { 42 };

Good: That does set s.d... :)

Ali

bearophile Wrote:

> This prints 42 0.000000 with the latest dmd2 and 42 nan with an older dmd1. It can be a bug:

It prints garbage here with 2.037. :/

As I've responded to my own post :), I think the initialization is meant only for static objects.

> 
> import std.c.stdio: printf;
> 
> struct S {
>     int i;
>     double d;
> }
> 
> void main() {
>     S s = { 42 };
>     printf("%d %f\n", s.i, s.d);
> }
> 
> Bye,
> bearophile

Ali

bearophile wrote:
> This prints 42 0.000000 with the latest dmd2 and 42 nan with an older dmd1.

You are unlucky then... ;) The following program leaves random values in s.d with dmd 2.037. Here is one output:

42 -0.008821

> It can be a bug:

Yes it is! :)

  http://d.puremagic.com/issues/show_bug.cgi?id=2485

Sorry for not finding it earlier; and thanks for you help.

> import std.c.stdio: printf;
>
> struct S {
>     int i;
>     double d;
> }
>
> void main() {
>     S s = { 42 };
>     printf("%d %f\n", s.i, s.d);
> }
>
> Bye,
> bearophile

Ali