You are correct that non-zero will be treated as true.
That's more an accident then anything else as everybody is checking "!= 0" for
true.
But the values need to be consistent in the "not" cases too if you want to be
safe about it. As I demonstrated in the code.
You want this to hold true, otherwise you'll get into trouble.
!!a == a
#include <stdio.h>
main()
{
int true1 = 1;
int true2 = -1;
printf("true = 1 OK? %s\n",(!!true1==true1)?"yes":"no");
printf("true =-1 OK? %s\n",(!!true2==true2)?"yes":"no");
}
true = 1 OK? yes
true =-1 OK? no
Michael D. Black
Senior Scientist
Advanced Analytics Directorate
Advanced GEOINT Solutions Operating Unit
Northrop Grumman Information Systems
________________________________
From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
behalf of Marc L. Allen [mlal...@outsitenetworks.com]
Sent: Thursday, April 19, 2012 2:56 PM
To: General Discussion of SQLite Database
Subject: EXT :Re: [sqlite] "DEFAULT BOOLEAN NOT NULL" not working with
entityframework
I was under the impression that, in C, 0 was false, non-zero was true.
> -----Original Message-----
> From: sqlite-users-boun...@sqlite.org [<thismessage:/>mailto:sqlite-users-
> boun...@sqlite.org] On Behalf Of Black, Michael (IS)
> Sent: Thursday, April 19, 2012 3:15 PM
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] "DEFAULT BOOLEAN NOT NULL" not working with
> entityframework
>
> Problem with true=-1.....
>
>
>
> !false=1
>
>
>
> So !false == true fails which can bite you in the behind
> unexpectedly....
>
>
>
> true= 1
> !true=0
> true=-1
> !true=0
> !false=1
> (true= 1 == !false) = 1
> (true=-1 == !false) = 0
>
>
>
> #include <stdio.h>
> main()
> {
> int true1=1;
> int true2=-1;
> int false=0;
> printf("true= 1\n!true=%d\n",!true1);
> printf("true=-1\n!true=%d\n",!true2);
> printf("!false=%d\n",!false);
> printf("(true= 1 == !false) = %d\n",true1==!false);
> printf("(true=-1 == !false) = %d\n",true2==!false); }
>
>
>
>
>
> Michael D. Black
>
> Senior Scientist
>
> Advanced Analytics Directorate
>
> Advanced GEOINT Solutions Operating Unit
>
> Northrop Grumman Information Systems
>
> ________________________________
> >>That is interesting to know, I tend to use -1 as true (misspent youth
> >>dabbling in Forth on 8 bit machines).
>
> _______________________________________________
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
