Given

    extern(C):

    struct AVFrame
    {
        uint8_t*[AV_NUM_DATA_POINTERS] data;
        int[AV_NUM_DATA_POINTERS] linesize;
        int width, height;
        ...
    }

    void av_image_copy(ubyte *[4] dst_data, int[4] dst_linesizes,
                       const ubyte *[4] src_data, const int[4] src_linesizes,
                       AVPixelFormat pix_fmt, int width, int height)


will `dst_data` will be C-ABI-fed to `image_copy()` as a C-style single pointer in constrast to what happens in D which calls it as fixed-size (4) array of ubyte-pointers?

Further, is it correct to use it in D as

    void copyVideo(const AVFrame* source,
                   AVFrame* target)
    {
        av_image_copy(target.data[0 .. 4], target.linesize[0 .. 4],
                      source.data[0 .. 4], source.linesize[0 .. 4],
                      format, source.width, source.height);
    }

?

It compiles without warnings, at least. I haven't been able to test it yet, though.

On Thursday, 9 July 2015 at 15:19:41 UTC, Nordlöw wrote:
>         uint8_t*[AV_NUM_DATA_POINTERS] data;
>         int[AV_NUM_DATA_POINTERS] linesize;

Forgot

    enum AV_NUM_DATA_POINTERS = 8;

On 07/09/2015 05:19 PM, "Nordlöw" wrote:
> Given
>
>      extern(C):
>
>      struct AVFrame
>      {
>          uint8_t*[AV_NUM_DATA_POINTERS] data;
>          int[AV_NUM_DATA_POINTERS] linesize;
>          int width, height;
>          ...
>      }
>
>      void av_image_copy(ubyte *[4] dst_data, int[4] dst_linesizes,
>                         const ubyte *[4] src_data, const int[4]
> src_linesizes,
>                         AVPixelFormat pix_fmt, int width, int height)
>
>
> will `dst_data` will be C-ABI-fed to `image_copy()` as a C-style single
> pointer in constrast to what happens in D which calls it as fixed-size
> (4) array of ubyte-pointers?

No. You'll need explicit pass by reference on the D side.

On Thursday, 9 July 2015 at 16:12:27 UTC, Timon Gehr wrote:
> No. You'll need explicit pass by reference on the D side.

So, how should I modify my call to `image_copy` with respect to the four first parameters?

On Thursday, 9 July 2015 at 17:11:36 UTC, Per Nordlöw wrote:
> On Thursday, 9 July 2015 at 16:12:27 UTC, Timon Gehr wrote:
>> No. You'll need explicit pass by reference on the D side.
>
> So, how should I modify my call to `image_copy` with respect to the four first parameters?

In C, array parameters are the same as pointers; i.e. `foo(T[] arg)` is the same as `foo(T* arg)` [1].

You should just be able to replace `[4]` with `*` in the arguments.

[1]: http://stackoverflow.com/a/5573741/646619

On Thursday, 9 July 2015 at 17:42:33 UTC, Alex Parrill wrote:
> On Thursday, 9 July 2015 at 17:11:36 UTC, Per Nordlöw wrote:
>> On Thursday, 9 July 2015 at 16:12:27 UTC, Timon Gehr wrote:
>>> No. You'll need explicit pass by reference on the D side.
>>
>> So, how should I modify my call to `image_copy` with respect to the four first parameters?
>
> In C, array parameters are the same as pointers; i.e. `foo(T[] arg)` is the same as `foo(T* arg)` [1].
>
> You should just be able to replace `[4]` with `*` in the arguments.
>
> [1]: http://stackoverflow.com/a/5573741/646619

Static arrays in C function parameter lists should be declared as ref on the D side. See "Passinbg D Array Arguments to C Functions" at [1]. So the function declaration above in D should be:

void av_image_copy(ref ubyte *[4] dst_data, ref int[4] dst_linesizes,
                       ref const ubyte *[4] src_data, ref const int[4] src_linesizes,
                       AVPixelFormat pix_fmt, int width, int height)

[1]http://dlang.org/interfaceToC.html

On Friday, 10 July 2015 at 03:18:23 UTC, Mike Parker wrote:
>> You should just be able to replace `[4]` with `*` in the arguments.
>
> [1]http://dlang.org/interfaceToC.html

Great!

One more thing: How shall my call to `avg_image_copy()` (from D) look then? Is the slicing syntax `[0 .. 4]` I use above as

    av_image_copy(target.data[0 .. 4], target.linesize[0 .. 4],
                  source.data[0 .. 4], source.linesize[0 .. 4],
                  format, source.width, source.height);

the best way?

On Friday, 10 July 2015 at 03:18:23 UTC, Mike Parker wrote:
> [1]http://dlang.org/interfaceToC.html

Is there any tool out there that automatically creates D wrappers from C headers`?

On Friday, 10 July 2015 at 08:42:06 UTC, Per Nordlöw wrote:
> On Friday, 10 July 2015 at 03:18:23 UTC, Mike Parker wrote:
>> [1]http://dlang.org/interfaceToC.html
>
> Is there any tool out there that automatically creates D wrappers from C headers`?

https://github.com/jacob-carlborg/dstep ?

On Friday, 10 July 2015 at 08:54:57 UTC, Andrea Fontana wrote:
>> Is there any tool out there that automatically creates D wrappers from C headers`?
>
> https://github.com/jacob-carlborg/dstep ?

Great! I'll try that!