> If there are no messages in the message queue,
 > read(2) will return no data and errno will be set to ENODATA.
 > If the buf argument to read(2) is not large enough to contain the message,
 > read(2) will return no data and errno will be set to EMSGSIZE.

read(2) will return -1 in these cases? If yes, then, please, write this.

Also, I see that you addressed all my requests. Thank you!

And thank you again for writing all these manpages!

--
Askar Safin
https://types.pl/@safinaskar