fix description formatting

src/cxxopts.cpp

@@ -101,14 +101,16 @@ namespace cxxopts
             result.append(startLine, current + 1);
             result.append("\n");
             result.append(start, ' ');
+            startLine = current + 1;
+            lastSpace = startLine;
           }
           else
           {
-            result.append(startLine, current);
+            result.append(startLine, lastSpace);
             result.append("\n");
             result.append(start, ' ');
+            startLine = lastSpace + 1;
           }
-          startLine = lastSpace + 1;
           size = 0;
         }
         else
@@ -405,7 +407,7 @@ Options::help() const
   longest = std::min(longest, static_cast<size_t>(OPTION_LONGEST));
 
   //widest allowed description
-  int allowed = 78 - longest - OPTION_DESC_GAP;
+  int allowed = 76 - longest - OPTION_DESC_GAP;
 
   auto fiter = format.begin();
   for (const auto& o : group->second)

src/example.cpp

@@ -40,6 +40,8 @@ int main(int argc, char* argv[])
       ("positional", 
         "Positional arguments: these are the arguments that are entered "
         "without an option", cxxopts::value<std::string>())
+      ("long-description",
+        "thisisareallylongwordthattakesupthewholelineandcannotbebrokenataspace")
       ("help", "Print help")
     ;