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Groups > comp.lang.c++ > #69968
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding |
| Date | 2019-11-22 00:37 -0800 |
| Organization | None to speak of |
| Message-ID | <lnsgmgxq5r.fsf@kst-u.example.com> (permalink) |
| References | (1 earlier) <lnr221zqmu.fsf@kst-u.example.com> <lnimndzq3i.fsf@kst-u.example.com> <qr5tre$mhv$1@dont-email.me> <qr6dgn$j2c$1@dont-email.me> <qr7v3c$lvv$1@dont-email.me> |
Christian Gollwitzer <auriocus@gmx.de> writes:
> Am 21.11.19 um 17:20 schrieb Paavo Helde:
[...]
>> However, for your purposes std::uint32_t should work fine.
>
> Why not
>
> #pragma pack(1)
> struct pixel {
> uint8_t red, green, blue, alpha;
> }
>
> ? That would make more sense to me than uint32_t and bit-twiddling to
> get the channel values.
Because #pragma pack is non-standard?
If you only care about implementations that support it as an extension,
that's fine, but the OP seemed very concerned about portability.
An array of uint8_t could also work:
typedef uint8_t pixel[4];
enum { red, green, blue, alpha };
Or an array wrapped in a struct to allow assignment. (An array of 4
uint8_t elements is guaranteed to be 32 bits, but a struct containing
such an array is not -- but it's a nearly safe assumption that there
will be no padding between the elements or at the end.)
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for Philips Healthcare
void Void(void) { Void(); } /* The recursive call of the void */
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[QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-20 19:55 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-20 20:12 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Keith Thompson <kst-u@mib.org> - 2019-11-20 22:33 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-20 20:22 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-11-20 19:34 +0000
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-21 00:54 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Öö Tiib <ootiib@hot.ee> - 2019-11-20 16:27 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Manfred <invalid@add.invalid> - 2019-11-21 01:48 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-21 04:09 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-20 17:44 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-21 04:14 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-20 22:03 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-21 01:00 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-21 13:22 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Keith Thompson <kst-u@mib.org> - 2019-11-21 11:30 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-21 22:54 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Paavo Helde <myfirstname@osa.pri.ee> - 2019-11-20 23:28 +0200
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-20 15:48 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Reinhardt Behm <rbehm@hushmail.com> - 2019-11-21 10:33 +0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-21 13:25 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Keith Thompson <kst-u@mib.org> - 2019-11-20 22:32 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Keith Thompson <kst-u@mib.org> - 2019-11-20 22:43 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-21 12:53 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Paavo Helde <myfirstname@osa.pri.ee> - 2019-11-21 18:20 +0200
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-21 18:07 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-11-21 17:34 +0000
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Christian Gollwitzer <auriocus@gmx.de> - 2019-11-22 07:26 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Keith Thompson <kst-u@mib.org> - 2019-11-22 00:37 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-22 10:10 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Öö Tiib <ootiib@hot.ee> - 2019-11-22 02:23 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-22 12:38 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Manfred <noname@add.invalid> - 2019-11-22 17:13 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-22 18:48 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-22 10:49 -0500
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-22 10:52 -0500
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-28 12:51 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-22 11:20 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Keith Thompson <kst-u@mib.org> - 2019-11-22 10:00 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-22 09:37 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Öö Tiib <ootiib@hot.ee> - 2019-11-22 01:37 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-22 11:40 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Öö Tiib <ootiib@hot.ee> - 2019-11-22 04:55 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-22 15:18 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Öö Tiib <ootiib@hot.ee> - 2019-11-22 07:23 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-22 16:34 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding scott@slp53.sl.home (Scott Lurndal) - 2019-11-22 15:16 +0000
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Öö Tiib <ootiib@hot.ee> - 2019-11-23 05:11 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-22 10:56 -0500
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Öö Tiib <ootiib@hot.ee> - 2019-11-23 07:03 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-22 11:31 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-22 12:23 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-22 13:14 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding David Brown <david.brown@hesbynett.no> - 2019-11-22 15:04 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-22 19:35 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-22 14:11 -0500
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-23 00:25 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-22 23:56 -0500
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-23 11:12 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Paavo Helde <myfirstname@osa.pri.ee> - 2019-11-23 14:51 +0200
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-25 11:45 -0500
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Keith Thompson <kst-u@mib.org> - 2019-11-22 22:04 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-23 11:26 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Keith Thompson <kst-u@mib.org> - 2019-11-23 12:27 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-24 00:54 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Keith Thompson <kst-u@mib.org> - 2019-11-23 17:06 -0800
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Soviet_Mario <SovietMario@CCCP.MIR> - 2019-11-24 12:10 +0100
Re: [QT creator on "nix"] - getting a strict 8 bit (1 byte) array with no padding Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-28 13:21 -0800
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