[Info-vax] Most popular application programming languages on VMS ?

[Arne Vajhøj]

On 1/10/2019 5:00 PM, Dave Froble wrote:
>> The CRTL uses the DLM with the range feature (don't think of them as
>> bytes in a file, but just a specialization of a normal named lock) to
>> be notified of multiple programs that are using the CRTL's
>> implementation of fcntl().
>>
>> http://pubs.opengroup.org/onlinepubs/9699919799/ and search for
>> "fcntl".
> 
> I'll take a look, but, I don't see how any resource name, being treated 
> solely as a resource name, could implement numeric range (better term 
> than byte range) locking.

Why not?

Traditional:

process A takes out lock on "FOOBAR"
process B tries to take out lock on "FOOBAR"
DLM tell B to wait because "FOOBAR" is taken

Range:

process A takes out lock on "FOOBAR" 1-1000
process B tries to take out lock on "FOOBAR" 501-1500
DLM tell B to wait because "FOOBAR" 501-1000 is taken

Arne