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| Path | csiph.com!eternal-september.org!feeder.eternal-september.org!mx02.eternal-september.org!.POSTED!not-for-mail |
|---|---|
| From | Keith Thompson <kst-u@mib.org> |
| Newsgroups | comp.lang.c |
| Subject | Re: Working with files on different operating systems |
| Date | Fri, 09 Oct 2015 16:57:53 -0700 |
| Organization | None to speak of |
| Lines | 40 |
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Les Cargill <lcargill99@comcast.com> writes:
> Keith Thompson wrote:
[Snipping stuff where we pretty much agree]
>> The value returned by ftell() is not guaranteed
>> to be meaningful, and neither fseek() nor ftell() is guaranteed to
>> work at all on all files. On Windows, the size of a file generally
>> does not match the number of characters that can be read from it
>> in text mode.
>
> This is an excellent reason not to use text mode. Text mode also
> can be related to, or ( on the right platforms ) may even use directly
> "cooked mode" from the old BIOS calls, and that's just wrong :)
Rather, I'd say it's an excellent reason not to assume that I can
predict exactly how many bytes I'll be able to read from a file in
text mode.
I'd rather use text mode than deal with the vagaries of "\r\n"
line endings and Ctrl-Z end-of-file markers myself.
If I need to slurp an entire text file into memory, and my code
only needs to be portable to POSIX and Windows systems, I think I
can assume that the size of the file (determined by whatever means
seem appropriate) is an upper bound on the number of bytes I'll
read (if I can also assume the file hasn't changed). The file size
should at least be a good first approximation of how much data I
can read from it. Of course, *always* check results and be prepared
for surprises.
And I'll acknowledge that there are times when slurping an entire
file into memory is a sensible thing to do (and times when it
definitely isn't).
[...]
--
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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Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 05:11 +0200
Re: Working with files on different operating systems Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-10-08 22:12 -0600
Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 00:18 -0500
Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-09 11:13 +0100
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 18:05 +0200
Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 12:49 -0500
Re: Working with files on different operating systems Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-09 17:32 -0400
Re: Working with files on different operating systems Ian Collins <ian-news@hotmail.com> - 2015-10-10 12:37 +1300
Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 12:48 -0500
Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-09 19:53 +0100
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 21:09 +0200
Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-09 20:28 +0100
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 21:40 +0200
Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 15:59 -0400
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 22:07 +0200
Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 16:24 -0400
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-10 03:08 +0200
Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-09 21:50 +0100
Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 14:54 -0400
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 21:05 +0200
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 21:47 +0200
Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 15:53 -0400
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 22:01 +0200
Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 16:05 -0400
Re: Working with files on different operating systems glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-10 01:16 +0000
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-10 03:46 +0200
Re: Working with files on different operating systems Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-10 08:08 -0400
Re: Working with files on different operating systems raltbos@xs4all.nl (Richard Bos) - 2015-10-10 17:02 +0000
Re: Working with files on different operating systems Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-09 15:53 -0400
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 18:00 +0200
Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 12:59 -0500
Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-09 12:37 -0700
Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 17:36 -0500
Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-09 16:52 -0700
Re: Working with files on different operating systems raltbos@xs4all.nl (Richard Bos) - 2015-10-14 11:27 +0000
Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-14 11:27 -0400
Re: Working with files on different operating systems Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-14 16:46 +0000
Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-14 10:18 -0700
Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-14 23:06 -0500
Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-09 09:16 -0700
Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 17:43 -0500
Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-09 16:57 -0700
Re: Working with files on different operating systems Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-09 22:41 -0700
Re: Working with files on different operating systems David Thompson <dave.thompson2@verizon.net> - 2015-10-31 06:50 -0400
Re: Working with files on different operating systems Siri Cruz <chine.bleu@yahoo.com> - 2015-10-08 23:25 -0700
Re: Working with files on different operating systems Geoff <geoff@invalid.invalid> - 2015-10-10 10:35 -0700
Re: Working with files on different operating systems Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-09 08:42 -0400
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 18:51 +0200
Re: Working with files on different operating systems Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-15 18:09 -0700
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-17 04:01 +0200
Re: Working with files on different operating systems Ian Collins <ian-news@hotmail.com> - 2015-10-17 15:55 +1300
Re: Working with files on different operating systems Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-16 20:09 -0700
Re: Working with files on different operating systems Ian Collins <ian-news@hotmail.com> - 2015-10-17 16:36 +1300
Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-17 05:10 +0200
Re: Working with files on different operating systems supercat@casperkitty.com - 2015-10-31 12:05 -0700
Re: Working with files on different operating systems Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-31 12:42 -0700
Re: Working with files on different operating systems supercat@casperkitty.com - 2015-10-31 13:40 -0700
Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-31 19:55 +0000
Re: Working with files on different operating systems supercat@casperkitty.com - 2015-10-31 13:43 -0700
Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-31 21:38 +0000
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