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| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: time |
| Date | 2012-11-21 12:30 -0800 |
| Organization | None to speak of |
| Message-ID | <lnzk2au2aq.fsf@nuthaus.mib.org> (permalink) |
| References | (1 earlier) <pan.2012.11.20.03.07.29.506000@nowhere.com> <8dd71a20-5caa-4e4a-8c1f-5c7d84b56bd2@h9g2000yqd.googlegroups.com> <50AD0DC6.5090505@verizon.net> <gof.1353524440.12609@somewhere.invalid> <k8jcq2$hmf$1@dont-email.me> |
"Bill Cunningham" <nospam@nspam.invalid> writes:
> Adam Wysocki wrote:
>> Maybe adding process ID to the seed calculation would do the job.
>>
>> Instead of:
>>
>> srand(time(NULL))
>>
>> Use:
>>
>> srand(time(NULL) ^ getpid())
>>
>> Or even:
>>
>> srand(time(NULL) ^ (getpid() << 16))
>
> Is that really that random? As long as a process has fork() 'ed and the
> process is running it's pid isn't going to change is it until the system
> kills it.
You only call srand() once during the execution of the program.
> btw to stay on-topic here that caret and those << indicators. I've
> never seen that in C except maybe headers. Are they preprocessing tokens?
^ is the exclusive-or operator. << is the left-shift operator.
You'll find both in the index of the C standard and of K&R, which
you could have checked before wasting everyone's time by asking
about it here.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Will write code for food.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-19 19:11 -0500
Re: time Geoff <geoff@invalid.invalid> - 2012-11-19 16:26 -0800
Re: time Keith Thompson <kst-u@mib.org> - 2012-11-19 16:51 -0800
Re: time Geoff <geoff@invalid.invalid> - 2012-11-19 17:01 -0800
Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-19 20:07 -0500
Re: time Keith Thompson <kst-u@mib.org> - 2012-11-19 23:54 -0800
Re: time pete <pfiland@mindspring.com> - 2012-11-20 07:31 -0500
Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-20 17:09 -0500
Re: time Keith Thompson <kst-u@mib.org> - 2012-11-19 16:30 -0800
Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-19 20:04 -0500
Re: time Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-11-25 05:52 -0800
Re: time Nobody <nobody@nowhere.com> - 2012-11-20 03:07 +0000
Re: time Keith Thompson <kst-u@mib.org> - 2012-11-19 23:58 -0800
Re: time Anand Hariharan <mailto.anand.hariharan@gmail.com> - 2012-11-21 08:30 -0800
Re: time "osmium" <r124c4u102@comcast.net> - 2012-11-21 11:11 -0600
Re: time James Kuyper <jameskuyper@verizon.net> - 2012-11-21 12:22 -0500
Re: time gof@somewhere.invalid (Adam Wysocki) - 2012-11-21 19:09 +0000
Re: time Keith Thompson <kst-u@mib.org> - 2012-11-21 12:01 -0800
Re: time gof@somewhere.invalid (Adam Wysocki) - 2012-11-23 08:15 +0000
Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-21 15:16 -0500
Re: time "osmium" <r124c4u102@comcast.net> - 2012-11-21 14:23 -0600
Re: time Rosario1903 <Rosario@invalid.invalid> - 2012-11-22 10:25 +0100
Re: time Keith Thompson <kst-u@mib.org> - 2012-11-21 12:30 -0800
Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-21 18:24 -0500
Re: time Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-11-25 05:56 -0800
Re: time Nobody <nobody@nowhere.com> - 2012-11-22 02:00 +0000
Re: time Keith Thompson <kst-u@mib.org> - 2012-11-21 19:57 -0800
Re: time gof@somewhere.invalid (Adam Wysocki) - 2012-11-23 08:31 +0000
Re: time army1987 <army1987@ask-for-it.invalid> - 2012-11-24 13:58 +0000
Re: time Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-22 11:36 +0000
Re: time gof@somewhere.invalid (Adam Wysocki) - 2012-11-23 08:20 +0000
Re: time Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-23 14:31 +0000
Re: time Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-11-25 05:54 -0800
Re: time Mark Storkamp <mstorkamp@yahoo.com> - 2012-11-20 08:34 -0600
Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-20 20:37 -0500
Re: time Keith Thompson <kst-u@mib.org> - 2012-11-20 20:25 -0800
Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-21 15:11 -0500
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