Geir Magnusson Jr wrote: > Tim Ellison wrote: >> This function is (deliberately) not exported from the hyprt.dll so you >> cannot call it directly. You have to call it via the function pointer >> table ... > > That's the missing element - it's not exported.
The idea is that code should always go via the function table so that your caller can control your use of these functions. >> Of course, you can reference that member directly if you so choose, and >> as written elsewhere if you are dealing with multiple tables the >> syntactic sugar doesn't help and you must reference it in full. > > When would you have multiple tables? Very rarely (Jimmy brought it up, so maybe he has an example). It would be more common to modify the table before you pass it on, to include a function that has more debug info (like the callsite version we saw earlier), or allocates from a given memory pool, or limits the amount of resource you can have, runs on a certain processor, etc. etc. >> I guess that the confusion is caused by the HyPortLib struct containing >> a member called 'mem_allocate_memory' that has the address of a function >> called 'hymem_allocate_memory'? > > really it was having a macro and a function named the same, differing > only by a number of arguments where the macro expanded out to what has > the potential of being something very different than the function > because of the function table. It wasn't obvious that the function > wasn't exported (of course). Right. As you see, the macro names follow a convention that matches the default table value function name -- once you are comfortable with that programming using the macros is not much different to programming direct to the function itself (modulo first portlib arg). Regards, Tim -- Tim Ellison ([EMAIL PROTECTED]) IBM Java technology centre, UK. --------------------------------------------------------------------- Terms of use : http://incubator.apache.org/harmony/mailing.html To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
