ROSCPP - reading HZ from code

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Hi Guys,

trying to figure out a way to read a HZ data of a rostopic in my C++ code. I see that there is no API for it, so I am trying to execute the cmd by using popen and reading from the file. However since it is a constant stream it makes the process to halt. Any idea what is the right way to do it? I need only one "iteration" of the data.

this is my current method that works for other calls:

std::string MyClass::InvokeCmd(std::string command)
{
    std::string result;
    std::array<char, 128> buffer;
    FILE *pipe = popen(command.c_str(), "r");

        while (fgets(buffer.data(), 128, pipe) != NULL)
        {
            result += buffer.data();
        }
    }
    pclose(pipe);
    return result;
}