> I use the following pseudo-code to better describe my problem:
>
> line 1: char *str1 = "test";
> 2: char *str2 = "example";
> 3: char *str3 = "this is an example that I run in my test
> program";
>
> 4: regex_t str1_re, str2_re;
>
> //I would like to compile str1 and str2 to regular
> expression. But I notice problem with line 6 already
> 5: regcomp(&str1_re, str1, 0);
> 6: regcomp(&str2_re, str2, 0); // when I watch str1_re and
> str2_re on ddd debugger, I saw str1_re got changed
> //
> after line 6. Is this right behavior?
nop. regcomp() only changes the regex_t structure that it receives. Make
sure you are really using PCRE (use ldd and check if you are linking against
PCRE).
> Basically, as I mentioned in the above C++ like comment, I would like to
> be able to compile 2 strings both into regular expressions then use them
> repeatedly to match other strings. Is this a feasible usage of PCRE
> library? I don't know what happens in 2nd regcomp (line 6) that changes
> the regular repression structure content I just compiled on line 5. Is
> there a way to get those two regex_t completely separated? Do I need to
> use some flag during compilation time?
You need to do it by hand. You can do it by building a new regex like: "(" +
str1 + ") | (" + str2 + ")"
This way you can also pray and eventually PCRE will optimize some stuff and
perform better than calling it twice :)
Nuno
