Well, in the first place, I always thought, that FTEST makes an direct check
on the file or device, omitting every TK2 occurence. Unfortunately, I was
wrong.
----- Original Message -----
From: "Dilwyn Jones" <[email protected]>
To: <[email protected]>
Sent: Tuesday, June 14, 2016 6:07 PM
Subject: Re: [Ql-Users] A feature or a bug?
Can someone explain this?
10 f$="":REMark empty string
20 if FTEST(f$)=0
30 DIR f$
40 ELSE
50 PRINT f$," can't be a file name"
60 ENDIF
Why is line 30 executed (displaying the directory of datad$) instead of
line 50?
IF line 30 is replace with VIEW f$ then the content of win (in my case
Win2_) is displayed.
Can someone confirm the above program?
François Van Emelen
FTEST("") is essentially FTEST(DATAD$) as Marcel and Tim have pointed out.
The TK2 extensions like this all pick up the system defaults.
a root drive name such as WIN1_ or WIN2_ on a level 2 system contains the
list of files details for the directory, as you'll see if you COPY WIN1_
TO SCR.
So, I would politely suggest you do NOT put DELETE or WDEL in line 30,
François!!! (unless you enjoy putting your win drives at risk of
self-destruct)
I daresay you could use a clumsy coding liek this to work around it:
5 d$=DATAD$:DATA_USE ""
10 f$=""
20 IF FTEST(f$)=0
...
70 DATA_USE d$
(even then there is a the risk another job might alter DATA_USE in between
lines of your program, just to screw things up, and beware of when DATAD$
returns just '_')
As an aside, the null filename used to be used (on level 1 filing systems)
in protection systems as a kind of hidden file in the early days of QL
software.
Dilwyn
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Version: 2016.0.7639 / Virus Database: 4604/12419 - Release Date: 06/14/16
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