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Groups > comp.lang.c++ > #82088
| From | David Brown <david.brown@hesbynett.no> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: I think references should have been const by default |
| Date | 2021-10-26 08:53 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <sl88lt$lc7$1@dont-email.me> (permalink) |
| References | (12 earlier) <sl5ug4$qov$1@gioia.aioe.org> <sl6ecq$11uu$1@gioia.aioe.org> <sl6go4$pjq$1@dont-email.me> <sl6l56$10d6$1@gioia.aioe.org> <sl83np$vf4$1@gioia.aioe.org> |
On 26/10/2021 07:29, Juha Nieminen wrote: > RacingRabbit@watershipdown.co.uk wrote: >> Any attempt to write to a read only program text area will result in a crash >> regardless of the language. > > There's absolutely nothing requiring C (or C++) compilers to put string > literals in a read-only memory segment. They are free to put them in a > normal read/write memory segment if they so wish. > > Nothing guarantees that the target architecture even *has* such a thing > as "read-only memory segments". > > This means that your program may well work "correctly" in one target > architecture but not in another. There is also nothing to guarantee that attempting to write to read-only memory will result in a "crash". It could result in nothing happening at all (the write being ignored), or a hang, or a reset of the entire system, or a write to somewhere different in memory. (I've worked with systems with all four such behaviours to at least some extent.) A particular /OS/ might guarantee that attempting to write to read-only memory segments results in a particular handling of the process, but it is certainly not guaranteed by C or C++. And of course, the C compiler might not actually attempt to make the write, but act as though it had. (I think that would be unlikely in practice, but it could be done for strings local to a function.) > >> It is implicit that its read only in C because >> C also provides the following initialisation which places the string >> (presumably) on the heap: >> >> char str[] = "hello world"; > > It cannot place it on the heap because that would just be a memory leak > (there would be nothing freeing it). It would allocate that array on > the stack, if it's inside a function (and if it's at the global scope, > whichever segment is dedicated to those). > (Hypothetically, it /could/ be allocated on the heap, or elsewhere, if the compiler also generated code to free it appropriately. While almost all C implementations use a stack for local data, there are a few exceptions.) > And that string literal there, if it actually gets generated into the > final binary, will still be in read-only memory (if the architecture > supports such a thing). It's just that its contents are copied to the > array when the array is allocated on the stack. > > (Btw, this is the reason why I say that C as "strings", rather than > strings. They are just char arrays, with a zero byte as an element > that by convention indicates the final character. This causes a > lot of confusion, especially since it induces many people to > think that a char* is a "string". Which it isn't. It's a pointer > to a value of type char. It *might* point to a null-terminated > char array, or it might not. It's not guaranteed that it's a > "string".) >
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I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-21 05:23 +0000
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-21 08:54 +0200
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-21 09:48 +0000
Re: I think references should have been const by default Paavo Helde <myfirstname@osa.pri.ee> - 2021-10-21 12:55 +0300
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-21 12:57 +0200
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-21 13:40 +0000
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-21 15:04 +0100
Re: I think references should have been const by default Manfred <noname@add.invalid> - 2021-10-21 16:41 +0200
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-21 14:57 +0000
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-21 14:51 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-21 12:09 -0400
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-21 23:49 +0100
Re: I think references should have been const by default "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2021-10-21 16:21 -0700
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-22 16:14 +0100
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-22 12:04 -0700
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-22 20:47 +0100
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-22 13:29 -0700
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-23 11:54 +0200
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-23 11:22 +0100
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-23 12:35 +0200
Re: I think references should have been const by default Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-10-23 13:23 +0100
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-23 13:57 +0100
Re: I think references should have been const by default Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-10-23 21:02 +0100
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-23 15:07 -0700
Re: I think references should have been const by default Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-10-23 21:15 -0700
Re: I think references should have been const by default Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-10-23 21:12 -0700
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-22 11:13 +0200
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-22 19:18 -0400
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-22 04:41 +0000
Re: I think references should have been const by default Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2021-10-23 21:30 +0100
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-25 04:51 +0000
Re: I think references should have been const by default Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2021-10-26 00:53 +0100
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-22 09:46 +0200
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-22 15:48 +0100
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-23 12:21 +0200
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-23 12:06 +0100
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-23 18:45 +0200
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-23 18:58 +0100
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-24 12:11 +0200
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-24 23:11 +0100
Re: I think references should have been const by default Öö Tiib <ootiib@hot.ee> - 2021-10-24 16:18 -0700
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-25 00:58 +0100
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-25 08:21 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-25 09:47 +0000
Re: I think references should have been const by default Bo Persson <bo@bo-persson.se> - 2021-10-25 12:33 +0200
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-25 14:19 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-25 10:59 -0400
Re: I think references should have been const by default Manfred <noname@add.invalid> - 2021-10-25 17:56 +0200
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-25 11:11 -0700
Re: I think references should have been const by default Manfred <noname@add.invalid> - 2021-10-26 17:15 +0200
Re: I think references should have been const by default Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-10-29 06:41 -0700
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-25 16:14 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-25 13:14 -0400
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 08:18 +0000
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-26 12:39 +0100
Re: I think references should have been const by default Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-10-26 14:29 +0100
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-26 15:11 +0100
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-26 09:49 -0700
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-26 18:38 +0100
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-26 11:20 -0700
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-26 20:32 +0100
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-26 22:18 +0200
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-27 04:43 +0000
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-27 08:29 +0200
Re: I think references should have been const by default Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-10-29 06:32 -0700
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-11-01 06:12 +0000
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-11-01 08:53 +0100
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-11-01 11:26 -0400
Re: I think references should have been const by default "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-11-02 16:19 +0100
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-11-02 12:54 -0400
Re: I think references should have been const by default Paavo Helde <myfirstname@osa.pri.ee> - 2021-11-02 23:49 +0200
Re: I think references should have been const by default "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-11-03 00:38 +0100
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 14:36 +0000
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-26 15:55 +0100
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 15:26 +0000
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-26 20:35 +0100
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-27 04:44 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 11:27 -0400
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 10:31 -0400
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 14:42 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 11:22 -0400
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 15:30 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 12:23 -0400
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 12:51 -0400
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 14:34 -0400
Re: I think references should have been const by default "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-10-26 12:57 -0700
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-27 07:57 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-27 08:47 +0000
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-27 14:29 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-28 05:17 +0000
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-28 09:30 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-29 04:47 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-29 05:11 +0000
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-29 08:40 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-11-01 06:15 +0000
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-27 11:07 +0200
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-27 14:30 +0000
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-27 17:30 +0200
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-27 15:46 +0000
Re: I think references should have been const by default scott@slp53.sl.home (Scott Lurndal) - 2021-10-27 16:13 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-27 11:39 -0400
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-27 15:51 +0000
Re: I think references should have been const by default Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-10-27 17:21 +0100
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-28 09:29 +0000
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-28 11:20 +0100
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-27 12:26 -0400
Re: I think references should have been const by default Anand Hariharan <mailto.anand.hariharan@gmail.com> - 2021-10-31 09:22 -0700
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-11-01 00:13 -0400
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-28 05:20 +0000
Re: I think references should have been const by default "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-10-27 23:10 -0700
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-28 09:30 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-29 04:51 +0000
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-29 08:39 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-11-01 06:34 +0000
Re: I think references should have been const by default Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2021-10-27 17:41 +0100
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-27 19:02 +0200
Re: I think references should have been const by default Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2021-10-27 18:21 +0100
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-27 11:38 -0400
Re: I think references should have been const by default JohnnyCameLater@whatsthetime.net - 2021-10-27 15:49 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-27 12:36 -0400
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-27 04:57 +0000
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-25 18:19 +0100
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-25 10:48 -0700
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 08:21 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-26 08:37 +0000
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 09:02 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-26 11:14 +0000
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 14:35 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-27 05:01 +0000
Re: I think references should have been const by default Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-10-29 06:34 -0700
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 10:43 -0400
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 15:21 +0000
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-26 22:32 +0200
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-27 05:04 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 10:42 -0400
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 14:48 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 11:52 -0400
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-26 10:22 -0700
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-26 10:27 -0700
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 14:06 -0400
Re: I think references should have been const by default Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-10-29 06:45 -0700
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-29 11:11 -0700
Re: I think references should have been const by default Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-04-25 07:39 -0700
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-04-25 10:59 -0700
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-26 05:29 +0000
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-26 08:53 +0200
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-26 08:23 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-26 08:40 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-26 05:18 +0000
Re: I think references should have been const by default David Brown <david.brown@hesbynett.no> - 2021-10-26 09:07 +0200
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-26 11:03 -0400
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-25 10:39 -0400
Re: I think references should have been const by default Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-25 10:56 -0700
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-25 10:30 -0400
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-25 14:39 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-25 11:05 -0400
Re: I think references should have been const by default "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-10-25 12:45 -0700
Re: I think references should have been const by default "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-10-26 11:20 -0700
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-25 05:00 +0000
Re: I think references should have been const by default Bart <bc@freeuk.com> - 2021-10-25 12:13 +0100
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-26 05:36 +0000
Re: I think references should have been const by default Manfred <noname@add.invalid> - 2021-10-25 16:58 +0200
Re: I think references should have been const by default "daniel...@gmail.com" <danielaparker@gmail.com> - 2021-10-22 12:28 -0700
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-21 09:12 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-21 09:52 +0000
Re: I think references should have been const by default RacingRabbit@watershipdown.co.uk - 2021-10-21 10:36 +0000
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-22 04:45 +0000
Re: I think references should have been const by default James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-21 12:07 -0400
Re: I think references should have been const by default Paavo Helde <myfirstname@osa.pri.ee> - 2021-10-21 12:18 +0300
Re: I think references should have been const by default Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-21 13:13 +0200
Re: I think references should have been const by default Bo Persson <bo@bo-persson.se> - 2021-10-21 15:08 +0200
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-22 04:45 +0000
Re: I think references should have been const by default Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-22 07:55 +0200
Re: I think references should have been const by default Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-22 11:21 +0000
Re: I think references should have been const by default "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-10-21 13:22 +0200
Re: I think references should have been const by default Juha Nieminen <nospam@thanks.invalid> - 2021-10-22 04:48 +0000
Re: I think references should have been const by default Manfred <noname@add.invalid> - 2021-10-21 13:57 +0200
Re: I think references should have been const by default Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-21 21:27 +0000
Re: I think references should have been const by default Jorgen Grahn <grahn+nntp@snipabacken.se> - 2021-10-24 14:20 +0000
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