用\0分割字符串保存到vector

把\0替换成其他字符，比如空格

//此处读取命令行
    std::fstream fs("/proc/self/cmdline");
    std::stringstream ss;
    ss << fs.rdbuf();
    std::string cmd = ss.str();
    LOG(INFO) << "cmd:" << cmd << std::endl;
    int pos_0 = cmd.find('\0');
    while (pos_0 != -1) {
        cmd.replace(pos_0, 1, " ");
        pos_0 = cmd.find('\0');
    }
    LOG(INFO) << "cmd:" << cmd << std::endl;

    //     Parse gflags.
    std::fstream fs("/proc/self/cmdline");
    std::stringstream ss;
    ss << fs.rdbuf();
    std::string cmd = ss.str();
    //    char* argv_temp[10000];
    //    int argc = 1;
    //    argv_temp[0] = &cmd[0];
    //    for (int i = 0; i < cmd.length() - 1; i++) {
    //        if (cmd[i] == '\0' && argc < 10) {
    //            if (strncmp(&cmd[i + 1], "--flagfile", 10)) {
    //                continue;
    //            }
    //            argv_temp[argc] = &cmd[i + 1];
    //            std::cout << "i= " << i << " argc=" << argc <<
    //            argv_temp[argc]; argc++;
    //        }
    //    }

    LOG(INFO) << "saved cmd:" << cmd << std::endl;
    int pos_0 = cmd.find('\0');
    while (pos_0 != -1) {
        cmd.replace(pos_0, 1, " ");
        pos_0 = cmd.find('\0');
    }
    LOG(INFO) << "original cmd:" << cmd << std::endl;

    // use C++11
    //    std::regex re_zero(" ");
    //    std::vector<std::string> cmd_vector(
    //            std::sregex_token_iterator(cmd.begin(), cmd.end(), re_zero,
    //            -1), std::sregex_token_iterator());

    // use string
    //    std::string delimiters = "\0";
    //    std::vector<std::string> cmd_vector;
    //    auto lastPos = cmd.find_first_not_of(delimiters, 0);
    //    auto pos = cmd.find_first_of(delimiters, lastPos);
    //    while (std::string::npos != pos || std::string::npos != lastPos) {
    //        cmd_vector.emplace_back(cmd.substr(lastPos, pos - lastPos));
    //        lastPos = cmd.find_first_not_of(delimiters, pos);
    //        pos = cmd.find_first_of(delimiters, lastPos);
    //    }

    // use strtok
    std::vector<std::string> cmd_vector;
    char cmd_char[cmd.length() + 1];
    int cmd_i = 0;
    for (cmd_i = 0; cmd_i < cmd.length(); cmd_i++) {
        cmd_char[cmd_i] = cmd[cmd_i];
    }
    cmd_char[cmd_i] = '\0';
    char* delim = (char*)" ";
    char* p = nullptr;
    std::string cmd_item = std::strtok(cmd_char, delim);
    cmd_vector.push_back(cmd_item);
    while ((p = std::strtok(nullptr, delim))) {
        std::string cmd_item_p = p;
        cmd_vector.push_back(cmd_item_p);
    }

    int argc = cmd_vector.size();
    char** argv = (char**)malloc(sizeof(char*) * argc);
    //    char argv[100][200];
    for (auto i = 0; i < argc; i++) {
        int len = cmd_vector[i].length();
        argv[i] = (char*)malloc(sizeof(char) * (len + 1));
        cmd_vector[i].copy(argv[i], len, 0);
        argv[i][len] = '\0';
        LOG(INFO) << "cmd item:" << argv[i] << std::endl;
    }