[Gambas-user] Catch NULL character

[nando]

Actually, the NULL character is a true character.
Specifically, it is CHR$(0)  <---zero.
It is an actual character in ASCII and other sets.

Alternatively, NULL is used in databases, Java, C, others
to describe certain situation.

Java: Null pointer is a pointer which has a value of zero and
therefore is an invalid reference and you'll get an exception.

C: Same thing, you'll get a seg fault or similar.

Databases: If the datatype is defined can be null, then the absence
of any value is NULL.  It is completely possible to have a VARCHAR
and not allow null and have a string stored with CHAR(zero) in it.
It is a NULL character and not the NULL situation.
The lack of any string is a NULL situation and not a NULL character.

Usually, the absence of assigning a variable a value will result in 
a NULL situation, not a NULL character.

Make sure you've got it correct or confusing results will follow.
-Fernando


---------- Original Message -----------
From: "Rodney Rundstrom" <iecltd at ...2113...>
To: "'mailing list for gambas users'" <gambas-user at lists.sourceforge.net>
Sent: Mon, 20 Apr 2009 10:56:29 +1200
Subject: Re: [Gambas-user] Catch NULL character

> As the NULL character is not a true character just a place holder you should
> use ISNULL(      )
> 
> Ie if ISNULL(NULL) Then print "GOT it"
> Just change NULL for your variable
> 
> Rodney Rundstrom
> 
> -----Original Message-----
> From: CelticBhoy [mailto:weldon_gary at ...67...] 
> Sent: Sunday, 29 March 2009 9:26 a.m.
> To: gambas-user at lists.sourceforge.net
> Subject: Re: [Gambas-user] Catch NULL character
> 
> Thanx again for the help. I will have a look at your advice and try and
> implement it in my code. This is my first crack at programming since way
> back in the QuickBasic days, so I appreciate the help.
> -- 
> View this message in context:
> http://www.nabble.com/Catch-NULL-character-tp22751957p22760874.html
> Sent from the gambas-user mailing list archive at Nabble.com.
> 
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------- End of Original Message -------