我正在使用boost::smatch对象从boost::regex_match获取匹配的模式,并将该匹配的模式字符串用于进一步的操作。在正常运行中它工作正常,但是当我使用Valgrind进行内存检查时,它在我正在读取匹配字符串即match.str(1)的行中显示错误。
我试图通过添加对smatch对象的大小的检查来消除此错误,但仍然会发生错误。

//[Modified function name because of policy]
if(boost::regex_match(arg_str,match,dcv::func_name_regex)
        && match.size() > 1) {
      std::string func_name = match.str(1);
      std::string modified_arg_str = replaceText(arg_str,func_name);

      lines.replace(
        func_lines.find(arg_str),
        arg_str.length(),
        modified_arg_str
      );
      continue;
    }
Valgrind输出为:
[Modified some filename and path because of policy]
3201  ==7723== Invalid read of size 1
3202  ==7723==    at 0x517259: snps_boost_1_72_0::sub_match<__gnu_cxx::__normal_iterator<char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >::str() const (../../include/boost/regex/v4/sub_match.hpp:84)
3203  ==7723==    by 0x516205: snps_boost_1_72_0::match_results<__gnu_cxx::__normal_iterator<char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<snps_boost_1_72_0::sub_match<__gnu_cxx::__normal_iterator<char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >::str(int) const (../../include/boost/regex/v4/match_results.hpp:207)
3204  ==7723==    by 0x50DDF7: Modifier::replaceText(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >) (/path/to/file.cpp:634)
3205  ==7723==    by 0x50D227: Modifier::functionArgument(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&) (/path/to/file.cpp:577)
无效读取位于读取匹配字符串的同一行。
std::string func_name = match.str(1);
我正在使用gcc-7.3.0和boost_1_72_0。

最佳答案

与ASAN / UBSAN / Valgrind一起运行的荣誉。你明白为什么它很重要:)
您正在读取未成功匹配的子组。您可能要检查是否做到了,仅检查size()>1是不够的:
Live On Coliru

#include <boost/regex.hpp>
#include <iostream>
#include <iomanip>

namespace dcv {
    boost::regex func_name_regex("z|(.)");
}

int main() {
    boost::smatch match;

    for (std::string arg_str: {"a","z"}) {
        if(boost::regex_match(arg_str, match, dcv::func_name_regex)) {
            std::cout << "Matched: " << std::quoted(arg_str) << " (" << match.size() << ")\n";
            if (match[1].matched) {
                std::string func_name = match.str(1);
                std::cout << "Subgroup matched: " << std::quoted(func_name) << "\n";
            } else {
                std::cout << "Subgroup NOT matched.\n";
            }
        }
    }

}
版画
Matched: "a" (2)
Subgroup matched: "a"
Matched: "z" (2)
Subgroup NOT matched.

关于c++ - 使用boost::smatch在valgrind中读取大小无效1,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/63147158/

10-11 22:36
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