Delighted to see strncat there, it's a buffer overflow waiting to happen, especially as the name sounds like it's the 'safer version' where it takes a size argu

Delighted to see strncat there, it's a buffer overflow waiting to happen, especially as the name sounds like it's the 'safer version' where it takes a size argument, except it's not the size of the destination buffer, it's the remaining size, so unless you know this, it's wrong for every non empty buffer. strlcat (not standard) operates how you expect.