+ if (file.length == 0 && line == 0)
+ return msg;
+ if (buffer.length == 0)
+ {
+ // Write into buffer[] the following: "file(line): msg"
+ buffer.length = 4 + file.length + line.sizeof * 3 + msg.length;
+ auto i = file.length;
+ buffer[0 .. i] = file[];
+ buffer[i] = '(';
+ i++;
+
+ auto n = line;
+ auto j = i;
+ do
+ {
+ buffer[i] = cast(char)((n % 10) + '0');
+ n /= 10;
+ i++;
+ } while (n);
+ buffer[j .. i].reverse;
+ buffer[i..i+3] = "): "[];
+ i += 3;
+
+ buffer[i .. i + msg.length] = msg[];
+ i += msg.length;
+
+ buffer = buffer[0 .. i];
+ }
+ return cast(invariant)buffer;