I am extracting each full row of a csv file using std::getline:

for (std::string row; std::getline(is, row); )  // reads entire row in csv file
{
    if (std::ranges::count(row, ',') != Temp_reading::read_parameters - 1) // checks if row has right amount of columns
    {
        std::cerr << "Row: " << row << " contains too many columns in csv file" << "n";
        is.unget(); // Want this to put entire row back into istream
        is.clear(std::ios_base::failbit);
        return;
     } 
     // does other stuff if the row has right amount of columns
 }

In this case is.unget() will only put back the last character in the istream. Is there a way to make is.unget() put back the entire row? Or is there another simple way to achieve the same?