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| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: trying a linked list |
| Date | 2016-05-08 19:31 -0700 |
| Organization | None to speak of |
| Message-ID | <lnd1owvu5z.fsf@kst-u.example.com> (permalink) |
| References | (10 earlier) <ngo3q2$r9a$1@dont-email.me> <87twi8fikb.fsf@bsb.me.uk> <ngoa7k$jg5$1@dont-email.me> <lnlh3kw6w4.fsf@kst-u.example.com> <ngodnh$2go$1@dont-email.me> |
"Bill Cunningham" <nospam@nspam.invalid> writes:
[snip]
> Thanks much Keith. I did not check to see if malloc worked or not. But I
> didn't think I'd have to set the pointer to NULL when I was going to use it.
> Does NULL "clear" it or something? Is that the problem with "dangling
> pointers"?
A null pointer doesn't point to anything. Yes, setting a pointer object
to NULL "clears" it.
An uninitialized pointer is garbage; attempting to use its value has
undefined behavior.
I'm not sure just what you mean by "I did not check to see if malloc
worked or not. But I didn't think I'd have to set the pointer to NULL
when I was going to use it." If you're going to assign a value to a
pointer, there's no need to set it to NULL first:
int *p = NULL; /* This initialization isn't necessary */
p = &something;
But a NULL pointer is used to mark the end of a linked list.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-07 17:06 -0400
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-07 17:32 -0400
Re: trying a linked list Rosario19 <Ros@invalid.invalid> - 2016-05-07 23:44 +0200
Re: trying a linked list "martin.ambuhl" <mambuhl@earthlink.net> - 2016-05-07 19:49 -0400
Re: trying a linked list Richard Heathfield <rjh@cpax.org.uk> - 2016-05-08 07:46 +0100
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-07 14:35 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-07 17:53 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-07 15:01 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-07 19:18 -0400
Re: trying a linked list Jerry Stuckle <jstucklex@attglobal.net> - 2016-05-07 19:28 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-07 16:40 -0700
Re: trying a linked list Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-05-07 17:15 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-07 20:25 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-07 20:10 -0700
Re: trying a linked list Richard Heathfield <rjh@cpax.org.uk> - 2016-05-08 07:53 +0100
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-08 14:19 -0700
Re: trying a linked list Manfred <mx2927@gmail.com> - 2016-05-08 18:45 +0200
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-08 17:21 -0400
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-08 14:38 -0400
Re: trying a linked list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-05-08 20:08 +0100
Re: trying a linked list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-05-08 20:26 +0100
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-08 17:22 -0400
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-08 15:28 -0400
Re: trying a linked list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-05-08 20:36 +0100
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-08 17:17 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-08 14:56 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-08 18:17 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-08 19:31 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 14:59 -0400
Re: trying a linked list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-05-08 23:22 +0100
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 14:46 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-08 14:32 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-08 18:05 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-08 14:26 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 13:50 -0400
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 14:08 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-09 11:38 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 14:50 -0400
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 14:51 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-09 13:51 -0700
Re: trying a linked list Ken Brody <kenbrody@spamcop.net> - 2016-05-09 17:53 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-09 13:47 -0700
Re: trying a linked list "Osmium" <r124c4u102@comcast.net> - 2016-05-09 15:58 -0500
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 17:13 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-09 14:35 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 17:40 -0400
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 17:41 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-09 15:10 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 22:02 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-09 21:17 -0700
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-09 22:31 -0400
Re: trying a linked list "Bill Cunningham" <nospam@nspam.invalid> - 2016-05-07 20:30 -0400
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-07 20:06 -0700
Re: trying a linked list Richard Heathfield <rjh@cpax.org.uk> - 2016-05-08 07:50 +0100
Re: trying a linked list BartC <bc@freeuk.com> - 2016-05-08 10:33 +0100
Re: trying a linked list Richard Heathfield <rjh@cpax.org.uk> - 2016-05-08 10:39 +0100
Re: trying a linked list BartC <bc@freeuk.com> - 2016-05-08 11:14 +0100
Re: trying a linked list Richard Heathfield <rjh@cpax.org.uk> - 2016-05-08 13:34 +0100
Re: trying a linked list BartC <bc@freeuk.com> - 2016-05-08 14:39 +0100
Re: trying a linked list Richard Heathfield <rjh@cpax.org.uk> - 2016-05-08 14:51 +0100
Re: trying a linked list Siri Cruise <chine.bleu@yahoo.com> - 2016-05-08 07:30 -0700
Re: trying a linked list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-05-08 10:36 +0100
Re: trying a linked list Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-05-08 02:49 -0700
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-08 14:17 -0700
Re: trying a linked list Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-05-08 14:36 -0700
Re: trying a linked list Keith Thompson <kst-u@mib.org> - 2016-05-08 14:57 -0700
Re: trying a linked list Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-05-09 13:28 -0700
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