I saw that there is a question about pthread sleep linux
However, when I looked up man page on my linux machine, I see the following.
unsigned int sleep(unsigned int seconds);
sleep() makes the current process sleep until seconds seconds
have elapsed or a
signal arrives which is not ignored.
The wording in your man page is likely wrong. Trust the standard and trust the man page on kernel.org. Write to the maintainer of the documentation for your distro and tell him to update the manual pages.