HChandler

QUOTE(TG @ Jul 31 2007, 11:43 AM) Excuse me as I make up my own jargon. I'm trying to learn the language of picture programming. OK so non-reentrant = static (and is easier to type) Is the VI's single existence in the context of the calling VI, or the top panel and all of it's children? And the spawn term is is more appropriately used in the context of the VI server?

QUOTE(xtaldaz @ Jul 31 2007, 11:46 AM) OK so lets say I have a sub-vi that is used to poll multiple devices. Because of the peculiarities of bus arbitration, there are long latencies in accessing these devices. What if it is desired that several devices be queried in parallel using the same vi. Say my vi has has an input control node to direct inquiries to different buses and/or devices. Do they still have to wait for completion? Can this behavior be changed either modally or programmatically? Thanks

Hi, I Have questions about the reentrant property. From what I gather, the normal behavior for vi's is that the data stored in them is "saved" between different calls to a non-reentrant vi, even though the vi might called in several different places in a given vi. Also, since for the default, non-reentrant mode, there is a single instance of this vi, and so subsequent calls to the same vi have to wait for completion of previous calls. Yes? I have a bunch more questions. If I call a non-reentrant vi from several different places within the same vi, only a single instance of this vi is created, with a single name space and program code space (correct?) , but when the re-entrant property is set, each iteration of the same vi spawns a new process, allocates new memory for variable storage and program code? Do all of these code instances persist throughout the life of the vi? Can they be freed without closing or leaving the vi in which they were created? Say I have a vi called nonReentrant.vi. If subVIa calls nonReentrant.vi and another vi, say subVIb calls nonReentrant, are both re-using the same code space, or to they each have their own instance of nonReentrant? On completion of either subvi does nonReentrant persist. If not is there a way to make it persistent? If so, is there a way to free it after you're done using it. Is there a way to make a vi conditionally reentrant? I'll probably have more questions after these are answered. Thanks for your patience

Has anyone built a set of tools for controlling Canon Powershot cameras (specifically the A-640 model. I'm looking for free here. I've downloaded canons SDK (PS-ReC SDK 1.1.0b) and might consider building my own bridge vi's if it doesn't seem too hard. The SDK includes C- based DLL's. I have heard that it's not too hard to access these from LV, but I've never done it so I would love it if someone could point me in the right direction for doing this. Of course, I would really love it if someone has already done this and was willing to share. Thanks,