- * the trailing NUL byte; but Windows's vsnprintf expects the
- * number of characters to write, and does not necessarily write the
- * trailing NUL.
+ * the trailing NUL byte; but Windows's vsnprintf uses the entire
+ * buffer and avoids the trailing NUL, should the buffer be exactly
+ * big enough for the result. Defining SNPRINTF_SIZE_CORR to 1 will
+ * therefore remove 1 byte from the reported buffer size, so we
+ * always have room for a trailing NUL byte.