CODEWITHSUNDEEP
c++regexc++11
Mauricio
Mauricio

Reputation: 742

regex ok but does not works

This code does not works, why?

std::cmatch result;
std::string str("trucmuch.service\n   Loaded: not-found (Reason: No such file or directory)\n   Active: inactive (dead)... (101)");
std::regex rgx("Loaded:\s+(\S+)(?:\s+\((?:Reason:\s*)?([^)]*)\))?", std::regex::ECMAScript);
std::regex_match(str.c_str(), result, rgx);
qDebug() << result.size();

Display 0 !!

How I can get result[0] and result1 ("not-found", "No such file or directory")?

Test on regex101

Upvotes: 0

Views: 58

Answers (1)

Kerrek SB
Kerrek SB

Reputation: 477640

Use std::regex_search to find substrings that match your pattern. You also need to escape the backslashes properly, or even better, use raw string literals. The following works:

#include <iostream>
#include <regex>
#include <string>

int main()
{
    std::smatch result;

    std::string str =
        "trucmuch.service\n   Loaded: not-found (Reason: No such file "
        "or directory)\n   Active: inactive (dead)... (101)";

    std::regex rgx(R"(Loaded:\s+(\S+)(?:\s+\((?:Reason:\s*)?([^)]*)\))?)",
                   std::regex::ECMAScript);

    std::regex_search(str, result, rgx);

    for (const auto & sm : result) { std::cout << sm << '\n'; }
}

Upvotes: 2

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