Converting string[] to char**

d

Solution

`std.algorithm.map` function returns range, which in your case must be changed into array. You can do this using `std.array.array`. Then you can get array pointer using `.ptr`. It returns `immutable(char**)` which is casted into `char**`:

extern (C) void init(int argc, char** argv);

void main(string[] args) {
    init(cast(int)args.length, cast(char**)map!(toStringz)(args).array.ptr);
}

Here's live demo: http://dpaste.dzfl.pl/ff81984c

Problem

Suppose I want to forward a set of command line options to a C function, declared as follows, with the D main taking args ``` extern (C) void init(int argc, char** argv); void main(string[] args) { init(args.length, map!(toStringz)(args)); } ``` The first parameter is easy enough, but my attempt at applying `toStringz` to the `args` array doesn't seem to work. I get `cannot implicitly convert expression (map(args)) of type MapResult!(toStringz,string[]) to char**`. How do you convert `string[]` to `char**` (or even `const(char)**`).

Original source