[Info-vax] VSI: "Official 8.4-1H1 Launch"

[John Reagan]

On Tuesday, June 16, 2015 at 7:26:29 AM UTC-4, Simon Clubley wrote:

> 
> When I wrote that, I wasn't thinking specifically about itemlists, but
> was responding to John's reference to using descriptors as a parameter
> passing mechanism instead of (for example) null terminated strings.
> 
> To respond to one of your later messages, with some higher level
> languages (for example Ada), you get the equivalent safety of
> descriptors (and more) because the language imposes it's own checks.
> 
> These languages also have higher level mechanisms so you don't have
> to do C-level copying of memory blocks around but can instead use a
> higher (and safer) level of abstraction.
> 

Even C went from things like "strcpy" to "strncpy" where the pointer & length are now part of the argument list.  Not exactly a descriptor, but the pieces of the descriptor are now part of the argument list.  F90 (and beyond) on Unix platforms usually flatten the "descriptors" for arrays et al into multiple arguments as well to pass address and length.

With OO languages where you can have smart classes to handle the data in a safe way, the "descriptor" becomes part of the class structure.