Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
| Message-ID | <500E17B1.2144@mindspring.com> (permalink) |
|---|---|
| Date | 2012-07-23 23:34 -0400 |
| From | pete <pfiland@mindspring.com> |
| Organization | PF |
| Newsgroups | comp.lang.c |
| Subject | Re: qsort man page |
| References | <89644623-7e1c-4f8b-9f4d-6443526f0f73@u2g2000yqj.googlegroups.com> |
Bill Cunningham wrote:
>
> This is from the qsort man page. I don't quite understand why there is
> a comment here saying that arguments to this generic function to pass
> to qsort is a pointer to pointer.
> It looks to me like cmpstringp takes
> a generic pointer. Not pointer to pointer. Why does the comment say
> pointer to pointer?
Because the argument that qsort will pass to cmpstringp,
when qsort calls cmpstringp,
is a pointer to a pointer.
> This is confusing me also with the strcmp
> parameters which are cast as a pointer to pointer and dereferenced.
The argument that qsort will pass to cmpstringp,
when qsort calls cmpstringp,
is a pointer to a pointer.
> static int
> cmpstringp(const void *p1, const void *p2)
> {
> /* The actual arguments to this function are "pointers to
> pointers to char", but strcmp(3) arguments are "pointers
> to char", hence the following cast plus dereference */
> return strcmp(* (char * const *) p1, * (char * const *) p2);
> }
--
pete
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
qsort man page Bill Cunningham <billcun@suddenlink.net> - 2012-07-21 14:14 -0700
Re: qsort man page Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-21 22:57 +0100
Re: qsort man page Bill Cunningham <billcun@suddenlink.net> - 2012-07-21 18:07 -0700
Re: qsort man page Mark Storkamp <mstorkamp@yahoo.com> - 2012-07-23 08:49 -0500
Re: qsort man page Bill Cunningham <billcun@suddenlink.net> - 2012-07-23 10:44 -0700
Re: qsort man page tom st denis <tom@iahu.ca> - 2012-07-26 09:02 -0700
Re: qsort man page John Gordon <gordon@panix.com> - 2012-07-26 16:41 +0000
Re: qsort man page tom st denis <tom@iahu.ca> - 2012-07-26 09:59 -0700
Re: qsort man page Ike Naar <ike@sverige.freeshell.org> - 2012-07-23 14:43 +0000
Re: qsort man page Bill Cunningham <billcun@suddenlink.net> - 2012-07-23 13:16 -0700
Re: qsort man page Barry Schwarz <schwarz45@yahoo.com> - 2012-07-23 13:29 -0700
Re: qsort man page Bill Cunningham <billcun@suddenlink.net> - 2012-07-23 16:56 -0700
Re: qsort man page Noob <root@localhost> - 2012-07-24 09:29 +0200
Re: qsort man page Keith Thompson <kst-u@mib.org> - 2012-07-24 23:17 -0700
Re: qsort man page Barry Schwarz <schwarz45@yahoo.com> - 2012-07-25 09:51 -0700
Re: qsort man page Bill Cunningham <billcun@suddenlink.net> - 2012-07-25 20:51 -0700
Re: qsort man page Barry Schwarz <schwarz45@yahoo.com> - 2012-07-26 14:27 -0700
Re: qsort man page Bill Cunningham <billcun@suddenlink.net> - 2012-07-26 18:20 -0700
Re: qsort man page Barry Schwarz <schwarz45@yahoo.com> - 2012-07-28 07:24 -0700
Re: qsort man page pete <pfiland@mindspring.com> - 2012-07-23 23:39 -0400
Re: qsort man page pete <pfiland@mindspring.com> - 2012-07-22 00:11 -0400
Re: qsort man page Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-22 14:41 +0100
Re: qsort man page pete <pfiland@mindspring.com> - 2012-07-22 13:01 -0400
Re: qsort man page Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-22 21:36 +0100
Re: qsort man page pete <pfiland@mindspring.com> - 2012-07-23 22:40 -0400
Re: qsort man page pacman@kosh.dhis.org (Alan Curry) - 2012-07-24 04:29 +0000
Re: qsort man page Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-24 11:40 +0100
Re: qsort man page pete <pfiland@mindspring.com> - 2012-07-24 22:06 -0400
Re: qsort man page Tim Rentsch <txr@alumni.caltech.edu> - 2012-09-07 11:38 -0700
Re: qsort man page pete <pfiland@mindspring.com> - 2012-07-23 23:34 -0400
Re: qsort man page pete <pfiland@mindspring.com> - 2012-07-24 00:07 -0400
Re: qsort man page "christian.bau" <christian.bau@cbau.wanadoo.co.uk> - 2012-07-24 16:36 -0700
csiph-web