[Info-vax] Command Procedure Pipe output to a variable

[Stephen Hoffman]

On 2021-10-08 15:47:22 +0000, Arne Vajhj said:

> On 10/8/2021 11:39 AM, Stephen Hoffman wrote:
>> On 2021-10-08 00:46:44 +0000, Lawrence D’Oliveiro said:
>>> If names are not symbols, then what are they?
>> 
>> Symbols are DCL variables, and are accessible within and local to DCL.
>> 
>> Logical names are I/O system variables, and are accessible to (most) 
>> file system clients.
> 
> Logical names are used all over for devices, directories and files.
> 
> But they are not limited to that.
> 
> They can be used for almost anything.
> 
> Including configuration settings. You may not like that usage, but it happens.

Those would all be among the file system clients mentioned, yes.

Less visible to inexperienced OpenVMS users, OpenVMS system parameters 
are even lower-level variables, though those with pre-defined names. A 
few of those system parameters are reserved for users.

Biggest confusion with symbols and logical names is that DCL can 
translate symbols and logical names as both DCL and the I/O system are 
visible within that context, but apps can only translate symbols when 
DCL is available within the current context.

Underpinning one of my grumbles about logical name usage and symbol 
usage is that OpenVMS lacks a common means and API for app 
configuration storage, which leads to other issues not the least of 
which are explosions of poorly-suited mechanisms including the use of 
DCL symbols and logical names and system parameters, and several dozen 
places where the "host name" resides. The volatile and 
printable-MCS-only logical name key-value store is also not a great fit 
for configuration data, discussions of its widespread (mis)use for that 
purpose aside. And yes, y'all can put app configuration settings down 
in the system parameters, too.



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