On Mon, Sep 22, 2008 at 6:19 AM, Igor Stasenko siguctua@gmail.com wrote:
2008/9/22 Gerardo Richarte gera@corest.com:
Igor Stasenko wrote:
2008/9/22 Gerardo Richarte gera@corest.com:
There's a native function I need to call (I called it 'aPrintf' in the code below) with a specific calling convention:
I wondering , why you prefer using string formatting in C, while in smalltalk you have own? You can easily format strings in smalltalk, and print only the resulting string w/o need in inventing safe schemes or conversion.
Hi Igor, nice to see you again!
I knew this was going to happen :)
It was just an example, I'm not using string formatting. The actual function I'm calling is the callout interface for OpenFirmware, through which OpenFirmware provides services to the booted operating system. Pretty much like BIOS' INT mechanism, but much more powerful.
Okay. Then i don't see any problems with this primitive, except maybe one thing:
a primitive should never change the contents of any argument(s). As in general smalltalk methods, a primitive should be allowed to change the contents only of receiver object, otherwise its breaking a smalltalk encapsulation rules. I would advice you to allocate separate byte array and fill it with values, then pass to C routine. Since its a byte array you don't need to care about it contents, and don't need a cleanup (GC will collect it as garbage eventually).
No need to use a Smalltalk object to hold the copy. Just use alloca (stack allocating version of malloc).
But this is the kind of thing an FFI does during marshalling anyway. Gerardo, why can't you use the FFI?