Hi there,

I'm learning D for a while because it's really easy to use C-code in D.
The problem is that I don't really get how to deal with the data structures defined in C in D.

At one time for instance I've tried to get all environment variables on a POSIX system. I succeeded but I think it can be done way easier.

So my question basically is:
1. How can I learn to use C code in D? Is there any good tutorial or other packages that deal with this a lot?
2. Is the way I'm currently doing it okay or is it wrong and do I need to do something else?

As a reference, I'm currently using the following D code to get all environment variables:

```
import std.array;
import std.conv: to;
import std.string: fromStringz;

extern (C) extern const char** environ;

string[string] getenv() {
	string[string] env;
	char* line;

	for (auto data = cast(char**)environ; (line = *data) != null; ++data) {
		auto keyval = to!string(fromStringz(line)).split('=');

		env[keyval[0]] = keyval[1];
	}

	return env;
}
```

On Thursday, 23 March 2017 at 18:10:20 UTC, Dillen Meijboom wrote:
> Hi there,
>
> I'm learning D for a while because it's really easy to use C-code in D.
> The problem is that I don't really get how to deal with the data structures defined in C in D.
>
> At one time for instance I've tried to get all environment variables on a POSIX system. I succeeded but I think it can be done way easier.
>
> So my question basically is:
> 1. How can I learn to use C code in D? Is there any good tutorial or other packages that deal with this a lot?
> 2. Is the way I'm currently doing it okay or is it wrong and do I need to do something else?
>
> As a reference, I'm currently using the following D code to get all environment variables:
>
> ```
> import std.array;
> import std.conv: to;
> import std.string: fromStringz;
>
> extern (C) extern const char** environ;
>
> string[string] getenv() {
> 	string[string] env;
> 	char* line;
>
> 	for (auto data = cast(char**)environ; (line = *data) != null; ++data) {
> 		auto keyval = to!string(fromStringz(line)).split('=');
>
> 		env[keyval[0]] = keyval[1];
> 	}
>
> 	return env;
> }
> ```

https://dlang.org/phobos/std_process.html#.environment means it's already done for you.

C global variables are __gshared.

Reading other people's source code - starting with standard library and maybe look at some of the bindings and wrappers on code.dlang.org.

IRC chat to get a quick answer most of the time.

On Thursday, 23 March 2017 at 18:10:20 UTC, Dillen Meijboom wrote:
> Hi there,
>
> I'm learning D for a while because it's really easy to use C-code in D.
> The problem is that I don't really get how to deal with the data structures defined in C in D.

D makes it easy to utilize C code, but there is no magic C to D wrapper. There are some functions in Phobos which help (e.g. toStringz). You can slice a C string to utilize it as a slice, but usually there are ownership issue with this approach. In my experience, you'll be writing some C style code to provide a D interface.

On Thursday, 23 March 2017 at 18:10:20 UTC, Dillen Meijboom wrote:
> Hi there,
>
> I'm learning D for a while because it's really easy to use C-code in D.
> The problem is that I don't really get how to deal with the data structures defined in C in D.

Perhaps, it will be interesting to you.
I advise to look at
https://www.youtube.com/watch?v=HTgJaRRfLPk