If we were strict, we should check every single fprintf() int write_tag() but it's highly improbable that some of the middle fprintf()s fail and the last one doesn't so the current implementation of write_tag() is probably sufficient.
If we were strict, we should check every single fprintf() int write_tag() but it's highly improbable that some of the middle fprintf()s fail and the last one doesn't so the current implementation of write_tag() is probably sufficient.