title: R function return value as well warning message
body: <p>I called other lib function, which does the calculation and throws warning message. I tried to use tryCatch() to capture the message but do not know how to keep the calculated value and the warning message. Here is sample (simplified) code, I would like mydiv function has both calculated value and warning message. Right now mydiv calls will return the division value or the warning but not both. </p>
  
  <pre><code>mydiv = function(x, y){  
  tryCatch({
  # raise warning message
  if (x &gt; y)
    warning("throw a warning")
    # function calc result
    x/y
  }, 
  warning = function(war) {
  flag = paste("DIV Warning:", war$message)
  return (flag)
  },
  error = function(err) {
   flag = paste("DIV Err", err)   
   return (flag)
  })
  }
  </code></pre>
  
  <p>If I call x = mydiv(2, 1) then the x has value "DIV Warning: throw a warning"; if x = mydiv(2, 4) then x: [1] 0.5. 
  So my question is: 1. use tryCatch: how to return the calculated value and warning message if possible; 2. whether there is a better approach to get both values from a function.</p>