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Groups > comp.lang.c > #149239
| From | T <T@invalid.invalid> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: C String terminator |
| Date | 2020-01-17 13:35 -0800 |
| Organization | A noiseless patient Spider |
| Message-ID | <qvt9ai$5tm$1@dont-email.me> (permalink) |
| References | (16 earlier) <87v9p9bylk.fsf@bsb.me.uk> <qvt6iq$j73$1@dont-email.me> <qvt6ts$l0m$1@dont-email.me> <FhpUF.71833$co3.19408@fx11.am4> <AzpUF.126441$QS6.40223@fx02.am4> |
On 2020-01-17 13:21, Bart wrote:
> On 17/01/2020 21:02, Bart wrote:
>> On 17/01/2020 20:54, T wrote:
>>> On 2020-01-17 12:48, T wrote:
>>
>>>>
>>>> Ben! I am an idiot when it comes to C. You
>>>> got to start out like I am a total noob!
>>>
>>> Okay, I looked at it from a bash standpoint instead
>>> of a mystery language I had no clue about. And I
>>> feel dumb. You were very precise!
>>>
>>> $ cd C
>>> $ vi t.c
>>> $ gcc -o t t.c
>>> $ t
>>> [FOOp@]
>>>
>>>
>>> Question: why did I get
>>> [FOOp@]
>>>
>>> and you got
>>> [FOO]
>>> ?
>>
>> Maybe you need a 0 terminator byte at the end of your "FOO" string.
>>
>> How else will printf know how long it is? All it has is a pointer to
>> the 'F' character at the start.
>>
>> Presumably, on one computer, there happened to be zero immediately
>> after the second 'O'; while on yours, "FOO" happened to be followed by
>> 'p' and '@' before it encountered a zero.
>>
>> (Haven't read the thread; perhaps it's been mentioned already...)
>
> BTW I changed the test program to this:
>
> ---------------------------------
> #include <stdio.h>
>
> void foo(const char *s)
> {
> for (int i=0; i<10; ++i)
> printf("%d ",*s++);
> puts("");
>
> }
>
> int main(void)
> {
> char str[3] = "FOO";
> foo(str);
> }
> ---------------------------------
>
> This prints the 3 characters codes of F,O,O in the string, plus 7 bytes
> that follow. Results on various compilers are as follows:
>
> bcc: 70 79 79 0 0 0 0 0 0 0
> tcc: 70 79 79 80 -1 18 0 0 0 0
> gcc -O0: 70 79 79 112 -14 48 0 0 0 0
> gcc -O3: 70 79 79 2 0 0 0 0 0 0
> lcc: 70 79 79 0 0 0 0 0 0 0
> dmc: 70 79 79 0 -120 -1 24 0 25 33
> clang -O0: 70 79 79 16 6 64 0 0 0 0
> clang -O2: 70 79 79 0 48 -120 73 6 -19 127
> msvc: 70 79 79 -29 -9 127 0 0 0 0
>
> The 70, 79, 79 are the F, O and O codes. When those 3 happen to be
> followed by 0, then it will appear to work.
>
> That is 4 out of 9, but the other 5 won't work. What follows after FOO
> is undefined and could be anything, although a random 0 is common.
>
Oh my gosh, I have now compiled TWO C programs.
I AM DANGEROUS!!!!
:-)
vi t2.c
$ gcc -o t2 t2.c
$ t2
70 79 79 -80 17 64 0 0 0 0
Okay, I know you guys said this clearly and directly,
but I can be thick as a stone at times: is the
-80 17 64 0 0 0 0
an example of careening until a proper terminator
is found?
-T
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C String terminator T <T@invalid.invalid> - 2020-01-14 09:22 -0800
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-01-14 09:32 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-14 09:43 -0800
Re: C String terminator Bart <bc@freeuk.com> - 2020-01-14 17:53 +0000
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-01-14 20:17 +0100
Re: C String terminator Bart <bc@freeuk.com> - 2020-01-14 20:01 +0000
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-01-14 09:57 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-14 11:37 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 09:02 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 09:38 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 09:53 -0800
Re: C String terminator Manfred <noname@add.invalid> - 2020-01-14 20:48 +0100
Re: C String terminator chad <cdalten@gmail.com> - 2020-01-15 05:43 -0800
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-01-15 07:12 -0800
Re: C String terminator Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-01-15 15:35 +0000
Re: C String terminator chad <cdalten@gmail.com> - 2020-01-19 06:20 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-15 10:52 -0800
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-01-15 12:52 -0800
Re: C String terminator gazelle@shell.xmission.com (Kenny McCormack) - 2020-01-15 20:56 +0000
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 02:17 +0000
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-15 21:54 -0800
Re: C String terminator fir <profesor.fir@gmail.com> - 2020-01-16 02:07 -0800
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-01-16 02:45 -0800
Re: C String terminator Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-01-16 08:21 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-01-16 08:03 -0800
Re: C String terminator John Bode <jfbode1029@gmail.com> - 2020-01-16 09:06 -0800
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-16 11:29 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 02:01 +0000
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-15 23:02 -0500
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-01-16 11:15 +0100
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 13:07 +0000
Re: C String terminator Manfred <noname@add.invalid> - 2020-01-17 18:43 +0100
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-21 04:00 -0800
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-21 05:00 -0800
Re: C String terminator Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-01-14 12:36 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-14 12:05 -0800
Re: C String terminator Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-01-14 13:54 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-14 15:03 -0800
Re: C String terminator Thiago Adams <thiago.adams@gmail.com> - 2020-01-15 04:55 -0800
Re: C String terminator Guillaume <message@bottle.org> - 2020-01-15 20:49 +0100
Re: C String terminator Thiago Adams <thiago.adams@gmail.com> - 2020-01-15 12:55 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-14 21:31 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 09:28 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 09:38 -0800
Re: C String terminator Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-01-15 10:50 -0700
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 10:17 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 09:53 -0800
Re: C String terminator Richard Damon <Richard@Damon-Family.org> - 2020-01-14 21:43 -0500
Re: C String terminator "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2020-01-14 22:52 -0800
Re: C String terminator "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2020-01-14 22:54 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-15 02:00 -0800
Re: C String terminator gazelle@shell.xmission.com (Kenny McCormack) - 2020-01-15 10:47 +0000
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-01-15 03:02 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 10:19 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-15 11:33 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 12:03 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 01:30 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 18:17 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 03:44 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 20:33 -0800
Re: C String terminator fir <profesor.fir@gmail.com> - 2020-01-16 02:26 -0800
Re: C String terminator Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-01-15 15:11 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 09:32 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-15 10:47 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 10:58 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 01:39 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 18:27 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 19:03 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 03:28 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 19:33 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 19:38 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 13:31 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-16 09:09 -0800
Re: C String terminator Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-01-16 10:27 -0700
Re: C String terminator T <T@invalid.invalid> - 2020-01-16 10:54 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 20:59 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-16 14:11 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 20:17 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-16 14:14 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 23:45 +0000
Yes, Ben makes house calls (Was: C String terminator) gazelle@shell.xmission.com (Kenny McCormack) - 2020-01-16 23:57 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-17 11:28 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-17 20:46 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-17 12:48 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-17 12:54 -0800
Re: C String terminator Bart <bc@freeuk.com> - 2020-01-17 21:02 +0000
Re: C String terminator Bart <bc@freeuk.com> - 2020-01-17 21:21 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-17 13:35 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-17 13:44 -0800
Re: C String terminator fir <profesor.fir@gmail.com> - 2020-01-17 15:03 -0800
Re: C String terminator fir <profesor.fir@gmail.com> - 2020-01-17 15:06 -0800
Re: C String terminator Ike Naar <ike@sdf.lonestar.org> - 2020-01-18 07:30 +0000
Re: C String terminator Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2020-01-17 16:06 -0500
Re: C String terminator Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2020-01-17 16:23 -0500
Re: C String terminator T <T@invalid.invalid> - 2020-01-17 13:37 -0800
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-21 04:10 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-21 10:41 -0800
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-01-17 01:55 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-17 09:52 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-17 11:29 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 18:21 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-16 10:50 -0800
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-01-16 20:50 +0000
Re: C String terminator T <T@invalid.invalid> - 2020-01-16 14:17 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-15 09:59 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-15 10:15 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-18 21:42 -0800
Re: C String terminator T <T@invalid.invalid> - 2020-01-19 22:13 -0800
Re: C String terminator Bonita Montero <Bonita.Montero@gmail.com> - 2020-01-21 19:49 +0100
Re: C String terminator John Bode <jfbode1029@gmail.com> - 2020-01-21 15:33 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-21 23:19 -0800
Re: C String terminator Bonita Montero <Bonita.Montero@gmail.com> - 2020-01-22 08:39 +0100
Re: C String terminator chad <cdalten@gmail.com> - 2020-01-22 06:59 -0800
Re: C String terminator Bonita Montero <Bonita.Montero@gmail.com> - 2020-01-22 18:44 +0100
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