Re: Regular expressions (multiple match problem)

On 2 huhti, 11:01, Antoninus Twink <nos...@nospam.invalid> wrote:
> On  2 Apr 2008 at  6:20, mikko.n wrote:
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> The problem is that you misunderstand what a match is.
>
> If the regex matches, then pm[0] contains the offsets of the (first)
> match for the whole regex. But pm[1],... don't contain the offets for
> subsequent matches of the whole regex, but rather contain the offsets of
> any parenthesized subexpressions that matched (in the match recorded in
> pm[0]).
>
> For example, try:
>
> #include <stdio.h>
> #include <regex.h>
> #include <sys/types.h>
>
> int main(void)
> {
>   regex_t p;
>   regmatch_t pm[2];
>   regcomp(&p,"k\\(.\\)",0);
>   regexec(&p,"mikko",2,pm,0);
>   printf("start=%d end=%d\n",pm[0].rm_so,pm[0].rm_eo);
>   printf("start=%d end=%d\n",pm[1].rm_so,pm[1].rm_eo);
>   regfree(&p);
>   return 0;
>
> }
>
> $ ./a
> start=2 end=4
> start=3 end=4

Is there then a simple alternative which would work so that it returns
all the matches of the original regexp in the text?

Mikko Nummelin

mikko.n wrote, On 02/04/08 09:37:
> On 2 huhti, 11:01, Antoninus Twink <nos...@nospam.invalid> wrote: 

<snip>

> Is there then a simple alternative which would work so that it returns
> all the matches of the original regexp in the text?

As Walter suggested, ask in a GNU group or mailing list where your
question would be topical (there is one specifically for regexp) instead
of comp.lang.c where it is not.

I note that this time you have added a cross post to
comp.unix.programmer where your question might be topical, but why
continue posting where it is not?
--
Flash Gordon

On  2 Apr 2008 at  8:37, mikko.n wrote:
> Is there then a simple alternative which would work so that it returns
> all the matches of the original regexp in the text?

Just use a loop, like this:


#include <stdio.h>
#include <regex.h>
#include <sys/types.h>

int main(void)
{
regex_t p;
regmatch_t pm;
char *s="mikko mikko";
regoff_t last_match=0;
regcomp(&p, "k", 0);
while(regexec(&p, s+last_match, 1, &pm, 0) == 0) {
printf("start=%d end=%d\n", pm.rm_so + last_match, pm.rm_eo + last_match);
last_match += pm.rm_so+1;
}
regfree(&p);
return 0;
}