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Groups > comp.lang.c > #103686
| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: better atoi |
| Date | 2017-02-11 17:33 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <871sv4y6mq.fsf@bsb.me.uk> (permalink) |
| References | (1 earlier) <1b1sv5k98w.fsf@pfeifferfamily.net> <c74e3f79-52b6-4c5a-b000-167ea48b26f0@googlegroups.com> <1bfujli90k.fsf@pfeifferfamily.net> <a8da9423-4e95-4ad5-be29-9499d341f331@googlegroups.com> <1b60kgirfs.fsf@pfeifferfamily.net> |
Joe Pfeiffer <pfeiffer@cs.nmsu.edu> writes:
> fir <profesor.fir@gmail.com> writes:
>>
>> well im not sure, could you tell maybe how i can check if
>> there was an out of range, or non numer , and number but with 'dirty'
>> input provided?
>
> Seriously? OK.
>
> #include <errno.h>
> #include <limits.h>
> #include <stdio.h>
> #include <stdlib.h>
>
> void checknum(const char *nptr, int base)
> {
> long int val;
> char *endptr;
>
> fprintf(stderr, "testing string \"%s\" in base %d\n", nptr, base);
> errno = 0;
> val = strtol(nptr, &endptr, base);
>
> if (val == LONG_MAX)
> fputs("value returned is LONG_MAX\n", stderr);
> else if (val == LONG_MIN)
> fputs("value returned is LONG_MIN\n", stderr);
> else
> fprintf(stderr, "value returned is %ld\n", val);
You have a problem here because the neither the description of fputs nor
of fprintf document the use of errno so either may set errno to non-zero
(even when there is no error!).
> if (errno != 0)
> perror("Error in input");
>
> if (endptr == nptr)
> fputs("string does not start with whitespace followed by number\n", stderr);
> else if (*endptr != '\0')
> fprintf(stderr, "more characters in string after number \"%s\"\n", endptr);
> else fputs("no characters in string after number\n", stderr);
>
> fputc('\n', stderr);
>
> }
<snip>
--
Ben.
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better atoi fir <profesor.fir@gmail.com> - 2017-02-10 12:24 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-10 12:35 -0800
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-10 14:48 -0700
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-10 14:12 -0800
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-10 22:36 -0700
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-11 01:07 -0800
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-11 10:10 -0700
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-11 09:26 -0800
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-11 15:36 -0700
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 00:18 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 00:31 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 03:47 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 04:22 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 06:08 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 06:13 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 07:31 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 08:02 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 08:08 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 08:17 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 08:23 -0800
Re: better atoi Robert Latest <boblatest@yahoo.com> - 2017-02-19 11:11 +0000
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-11 17:33 +0000
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-11 15:35 -0700
Re: better atoi "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-11 17:52 -0500
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-11 18:53 -0700
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-10 22:50 +0000
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-10 21:59 -0700
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-11 12:08 +0000
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-11 09:39 -0700
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-11 17:26 +0000
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-11 15:30 -0700
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-11 22:58 +0000
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-11 18:48 -0700
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-12 02:16 +0000
Re: better atoi "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-12 09:57 -0500
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 07:27 -0800
Re: better atoi jameskuyper@verizon.net - 2017-02-12 08:44 -0800
Re: better atoi fir <profesor.fir@gmail.com> - 2017-02-12 09:15 -0800
Re: better atoi Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-02-12 09:44 -0800
Re: better atoi BartC <bc@freeuk.com> - 2017-02-12 18:32 +0000
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-12 18:56 +0000
Re: better atoi BartC <bc@freeuk.com> - 2017-02-12 19:18 +0000
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-13 00:16 +0000
Re: better atoi BartC <bc@freeuk.com> - 2017-02-13 01:56 +0000
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-13 10:44 +0000
Re: better atoi BartC <bc@freeuk.com> - 2017-02-13 11:38 +0000
Re: better atoi Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-13 14:37 +0000
Re: better atoi BartC <bc@freeuk.com> - 2017-02-13 15:00 +0000
Re: better atoi Keith Thompson <kst-u@mib.org> - 2017-02-12 11:15 -0800
Re: better atoi BartC <bc@freeuk.com> - 2017-02-12 19:25 +0000
Re: better atoi Keith Thompson <kst-u@mib.org> - 2017-02-12 11:54 -0800
Re: better atoi supercat@casperkitty.com - 2017-02-12 13:13 -0800
Re: better atoi Keith Thompson <kst-u@mib.org> - 2017-02-10 15:16 -0800
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-10 22:01 -0700
Re: better atoi Keith Thompson <kst-u@mib.org> - 2017-02-11 01:30 -0800
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-10 22:26 -0700
Re: better atoi Nick Bowler <nbowler@draconx.ca> - 2017-02-11 00:26 +0000
Re: better atoi Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-02-10 22:32 -0700
Re: better atoi "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-19 11:10 -0500
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