GetDataInstance and GetParameter in TagData Read

[Helper]

On 16/09/2016 at 00:47, xxxxxxxx wrote:

User Information:
Cinema 4D Version:   R17 
Platform:   Windows  ;   
Language(s) :     C++  ;

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Hello.

I have a filename parameter, which I try to retrieve in Read method (TagData plugin).

Here is the code using GetDataInstance and GetParameter

//1
BaseContainer* tag_data = tag->GetDataInstance();
String filename = tag_data->GetFilename(FILENAME_PARAM).GetString();
  
//2
GeData ge_data;
tag->GetParameter(FILENAME_PARAM, ge_data, DESCFLAGS_GET_PARAM_GET);
String filename = ge_data.GetFilename().GetString();

The first filename gets the value correctly, while the second filename string appears empty.
Why GetParameter doesn't return the value correctly ?

Thank you.

[Helper]

On 16/09/2016 at 02:07, xxxxxxxx wrote:

Hi,

you are using DESCFLAGS_GET_PARAM_GET, which is the flag for saying, the parameter got read successfully. Can you please try, if the problem persists, if you use DESCFLAGS_GET_0 instead?

[Helper]

On 16/09/2016 at 05:44, xxxxxxxx wrote:

Hello.

Using DESCFLAGS_GET_0 returns the correct value. So I assume that whenever I want to read a parameter, I have to use DESCFLAGS_GET_0 right ?
When am I supposed to use DESCFLAGS_GET_PARAM_GET ?

Thank you for your time.

[Helper]

On 16/09/2016 at 05:50, xxxxxxxx wrote:

Hi,

DESCFLAGS_GET_PARAM_GET is used inside GetDParameter() to mark the successful retrieval of the parameter. You don't pass it into GetParameter().

[Helper]

On 16/09/2016 at 06:16, xxxxxxxx wrote:

Hello.

I didn't know that. I assume SET_PARAM_SET does the same right (in SetDParameter)?

thnx.

[Helper]

On 16/09/2016 at 08:56, xxxxxxxx wrote:

Yes. Sorry, I got disturbed, while posting. I actually wanted to mention this in my post.

[Helper]

On 16/09/2016 at 09:01, xxxxxxxx wrote:

Even worse, I forgot to post the links to our documentation.
Manuals on GetDParameter() and SetDParameter() and here the API reference: GetDParameter() and SetDParameter().