On 22 November 2013 05:09, Sean P. DeNigris <sean@clipperadams.com> wrote:

Igor Stasenko wrote

>> The better way is to subclass from NBExternalObject then
> which made exactly for such purposes, by holding an opaque handle to
> something (you don't care what is inside), and simplifies a lot of things.

I made "NBExternalObject subclass: #FMOD_SYSTEM".
I then tried to use it via:
�� system := FMOD_SYSTEM new.
�� err := self System_CreateNBExternalObject: system.
With callout:
�� ^ self nbCall: #(FMOD_RESULT FMOD_System_Create(NBExternalObject system)).

For the argument type in the signature, for good measure I tried:
1. NBExternalObject
2. FMOD_SYSTEM
3. NBExternalAddress
All three with zero, one, and two *'s after. The only one that didn't report
some variety of "An instance of Xyz expected" was
"FMOD_System_Create(FMOD_SYSTEM system)" for which the library returns an
invalid argument error code.

yet again, you miss the right solution: you must pass a pointer to where value will be stored

(since function doing exactly that).

so you should do it like:
1. "NBExternalObject subclass: #FMOD_SYSTEM".

2. method to call the function will look like following:
�� create: system

�� ^ self nbCall: #(FMOD_RESULT FMOD_System_Create(FMOD_SYSTEM * system)).

3. and call it like following:

�� system :=�� FMOD_SYSTEM new.

�� self handleError: (self create: system) ifOk: [ ^ system ]

3a. optionally, you want want to initialize it just after you know that you obtained correct handle,

to do that, you could do following:

FMOD_SYSTEM class>>new

�� | system |

�� system :=�� super new.
�� self handleError: (self create: system) ifOk: [ ^ self newWithHandle: system handle ]

and newWithHandle: could look something like following:

newWithHandle: aHandle

��system := super basicNew.

��system handle: aHandle.

��^ system initialize

(because it is important to set the handle first, like that you can actually initialize something more

by using it, which you logically do, just after creating a new handle.

and note you must not call 'super initialize' then, because it will reset handle.)

and i'm sure you can find more elegant solution :)

btw if anyone wants to play with it:
1.
�� Gofer it
�� smalltalkhubUser: 'SeanDeNigris' project: 'FMOD';
�� package: 'FMOD';
�� load.

2. Download the FMOD library for your platform:
- windows -
http://www.fmod.org/download/fmodstudio/api/Win/fmodstudioapi10208win-installer.exe
- Mac -
http://www.fmod.org/download/fmodstudio/api/Mac/fmodstudioapi10208mac-installer.dmg

3. Copy the library to "FileLocator imageDirectory / 'FMOD Programmers
API/api/lowlevel/lib/libfmod.dylib'"

The working example is:
| sound |
sound := FmodSound fromFile: '/path/to/file.mp3' asFileReference.
[ sound play ] fork.

The broken one described above is: "FMOD exampleNBExternalObject."

-----
Cheers,
Sean
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--
Best regards,
Igor Stasenko.