Groups | Search | Server Info | Keyboard shortcuts | Login | Register
Groups > comp.os.linux.misc > #37437
| Subject | Re: Contents of file changed while application is reading it |
|---|---|
| Newsgroups | comp.os.linux.misc |
| References | (16 earlier) <qPadnQSthu_CfJ_5nZ2dnZfqn_ednZ2d@earthlink.com> <wwvcz5o7sfd.fsf@LkoBDZeT.terraraq.uk> <CtScnbUpEtjMcp75nZ2dnZfqnPWdnZ2d@earthlink.com> <tu264t$vn7i$18@dont-email.me> <tu2g16$1crqf$1@dont-email.me> |
| From | "28B.I874" <28B.I874@noabzba.net> |
| Organization | gear transect |
| Date | 2023-03-06 01:21 -0500 |
| Message-ID | <FgWdnThtdob-G5j5nZ2dnZfqn_udnZ2d@earthlink.com> (permalink) |
On 3/5/23 11:29 AM, Dan Espen wrote:
> The Natural Philosopher <tnp@invalid.invalid> writes:
>
>> On 05/03/2023 01:24, 28B.I874 wrote:
>>> On 3/4/23 4:54 AM, Richard Kettlewell wrote:
>>>> "28A.I873" <28A.I873@noabzba.net> writes:
>>>>> Ah ... an interesting technical question about 'C' ...
>>>>> assume you're looking for the position of a given
>>>>> character in a string .......
>>>>>
>>>>> for(x=0;x<strlen(TheStr);x++)
>>>>> {
>>>>> if(TheStr[x]==TheChar) return(x);
>>>>> }
>>>>> return(-1);
>>>>>
>>>>> is a pretty common approach. HOWEVER, the QUESTION,
>>>>> is "strlen(TheStr)" calculated over and over again
>>>>> for every iteration ??? That seems SLOW, esp if
>>>>> TheStr is BIG.
>>>>
>>>> The short answer to your question is: stop hand-coding the search and
>>>> use strchr.
>>> The above was just an example. Usually you'd want
>>> to do a lot more than JUST find the index of TheChar.
>>> strchr() gets rid of those few lines of code, but
>>> what is IT doing, how they code it ? Same thing ?
>>> Kinda has to be. I can dig into the .h and see ...
>>>
>> I would code it - if its what think it is, as
>>
>> char *strchr( char *p, char a)
>
> I believe if you look at string.h you might see that gcc goes a bit
> farther toward optimizing than any C code would do.
We'll have to check. A few issues have been mentioned here
and I think they deserve at least a little investigation
and/or benchmarking. There are trix and then there are the
PERFECT trix. Lots of lib routines involve scanning down
a string in one or more places, so it's important.
DID like Mr.Natural's pointery solution to the basic 'find
char in string'. It'll be in my next projects (with creds).
Note that strtok() does NOT take a char as the delimiter but
a STRING ... ie you can have multiple delims. I've used this
to advantage in ascii-delimited multivalue DB records (which
I sometimes make for simple apps - SO easy to assemble as you
go along). Easy to read also. ('general-purpose' EDITING, well,
that's not so easy ... "intent" becomes involved as there are
a number of ways to structure fields/sub-fields/sub-sub-fields)
Back to comp.os.linux.misc | Previous | Next — Previous in thread | Next in thread | Find similar
Contents of file changed while application is reading it Clark Smith <noaddress@nowhere.net> - 2023-02-26 18:52 +0000
Re: Contents of file changed while application is reading it Rich <rich@example.invalid> - 2023-02-26 19:20 +0000
Re: Contents of file changed while application is reading it Robert Heller <heller@deepsoft.com> - 2023-02-26 21:45 +0000
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-02-26 23:05 +0100
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-02-26 23:38 +0000
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-02-26 23:32 +0000
Re: Contents of file changed while application is reading it "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2023-02-26 19:06 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-02-27 00:26 +0000
Re: Contents of file changed while application is reading it "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2023-02-26 20:48 -0500
Re: Contents of file changed while application is reading it Richard Kettlewell <invalid@invalid.invalid> - 2023-02-27 09:03 +0000
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-02-27 09:58 +0000
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-02-27 11:16 +0100
Re: Contents of file changed while application is reading it Richard Kettlewell <invalid@invalid.invalid> - 2023-02-27 15:20 +0000
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-02-27 10:34 +0100
Re: Contents of file changed while application is reading it Richard Kettlewell <invalid@invalid.invalid> - 2023-02-27 09:49 +0000
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-02-27 11:13 +0100
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-02-27 10:02 +0000
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-02-27 11:13 +0100
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-02-27 10:17 +0000
Re: Contents of file changed while application is reading it "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2023-02-27 12:27 -0500
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-02-27 19:19 +0100
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-02-27 21:46 -0500
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-02-28 13:33 +0100
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-02-28 10:49 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-02-28 16:21 +0000
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-01 01:05 -0500
Re: Contents of file changed while application is reading it Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2023-03-01 21:57 +0000
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-01 22:53 -0500
Re: Contents of file changed while application is reading it Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2023-03-02 19:06 +0000
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-02 23:08 -0500
Re: Contents of file changed while application is reading it Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2023-03-03 05:23 +0000
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-03 09:36 +0000
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-03-03 11:19 +0100
Re: Contents of file changed while application is reading it Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2023-03-03 15:58 +0000
Re: Contents of file changed while application is reading it "Carlos E. R." <robin_listas@es.invalid> - 2023-03-03 18:47 +0100
Re: Contents of file changed while application is reading it Rich <rich@example.invalid> - 2023-03-04 16:24 +0000
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-03-04 18:40 +0100
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-03 18:44 +0000
Re: Contents of file changed while application is reading it Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2023-03-04 01:25 +0000
Re: Contents of file changed while application is reading it Rich <rich@example.invalid> - 2023-03-04 16:21 +0000
Re: Contents of file changed while application is reading it "28B.I874" <28B.I874@noabzba.net> - 2023-03-04 23:55 -0500
Re: Contents of file changed while application is reading it Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2023-03-05 05:35 +0000
Re: Contents of file changed while application is reading it Allodoxaphobia <trepidation@example.net> - 2023-03-05 13:48 +0000
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-05 14:01 +0000
Re: Contents of file changed while application is reading it Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2023-03-05 19:16 +0000
Re: Contents of file changed while application is reading it "28B.I874" <28B.I874@noabzba.net> - 2023-03-06 00:43 -0500
Re: Contents of file changed while application is reading it "28B.I874" <28B.I874@noabzba.net> - 2023-03-06 00:42 -0500
Re: Contents of file changed while application is reading it "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2023-02-28 12:01 -0500
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-01 01:17 -0500
Re: Contents of file changed while application is reading it Robert Riches <spamtrap42@jacob21819.net> - 2023-02-28 04:13 +0000
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-02-28 13:16 +0100
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-01 01:32 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-01 10:30 +0000
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-01 22:48 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-02 09:41 +0000
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-02 23:39 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-03 09:28 +0000
Re: Contents of file changed while application is reading it "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2023-03-03 12:16 -0500
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-04 01:36 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-04 07:15 +0000
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-04 02:47 -0500
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-04 01:12 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-04 06:51 +0000
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-03-04 03:32 -0500
Re: Contents of file changed while application is reading it Richard Kettlewell <invalid@invalid.invalid> - 2023-03-04 09:54 +0000
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-04 10:09 +0000
Re: Contents of file changed while application is reading it Richard Kettlewell <invalid@invalid.invalid> - 2023-03-04 11:22 +0000
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-04 11:58 +0000
Re: Contents of file changed while application is reading it Richard Kettlewell <invalid@invalid.invalid> - 2023-03-05 16:43 +0000
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-06 09:20 +0000
Re: Contents of file changed while application is reading it "28B.I874" <28B.I874@noabzba.net> - 2023-03-04 20:24 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-05 13:40 +0000
Re: Contents of file changed while application is reading it Dan Espen <dan1espen@gmail.com> - 2023-03-05 11:29 -0500
Re: Contents of file changed while application is reading it "28B.I874" <28B.I874@noabzba.net> - 2023-03-06 01:21 -0500
Re: Contents of file changed while application is reading it "28B.I874" <28B.I874@noabzba.net> - 2023-03-06 01:06 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-03-06 09:28 +0000
Re: Contents of file changed while application is reading it "28B.I874" <28B.I874@noabzba.net> - 2023-03-06 08:54 -0500
Re: Contents of file changed while application is reading it Dan Espen <dan1espen@gmail.com> - 2023-02-26 17:35 -0500
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-02-26 23:39 +0000
Re: Contents of file changed while application is reading it "28A.I873" <28A.I873@noabzba.net> - 2023-02-26 22:42 -0500
Re: Contents of file changed while application is reading it "Carlos E.R." <robin_listas@es.invalid> - 2023-02-27 10:45 +0100
Re: Contents of file changed while application is reading it The Natural Philosopher <tnp@invalid.invalid> - 2023-02-26 23:31 +0000
csiph-web