From: ma740988@gmail.com
Subject: if Restrict_Func /= null confusion
Date: Sun, 30 Mar 2008 13:58:02 -0700 (PDT)
Date: 2008-03-30T13:58:02-07:00 [thread overview]
Message-ID: <95f36a62-b94c-4211-896a-300fa98932b7@x41g2000hsb.googlegroups.com> (raw)
Well folks its been at least 4 years since I've perused and/or written
Ada source. That aside I'm perusing source code written in Ada. So
consider:
-- used to restrict a variable within a range
-- for example: -PI to +PI
type Restrict_Function is access function (X: Real4) return Real4;
type Filt_Data is
record
Restrict_Func : Restrict_Function ;
end record ;
-- within a procedure we have
Fdata : Filt_Data;
Restrict_Func : Restrict_Function := FData.Restrict_Func ;
if Restrict_Func /= null then
-- stuff
endif
At issue: I'm not following the conditional logic 'if (Restrict_Func /
= null)'. Not understanding the impetus behind the check for null.
next reply other threads:[~2008-03-30 20:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-30 20:58 ma740988 [this message]
2008-03-30 21:34 ` if Restrict_Func /= null confusion jimmaureenrogers
2008-03-30 21:36 ` Ludovic Brenta
2008-03-30 21:37 ` Robert A Duff
2008-03-30 21:44 ` Georg Bauhaus
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