Man pages matching name h_errno in section 3:

h_errno.3.de	debian 10 / manpages-de-dev
h_errno.3.en	debian 10 / manpages-dev
h_errno.3.ja	debian 10 / manpages-ja-dev
h_errno.3.pl	debian 10 / manpages-pl-dev
h_errno.3.de	debian 11 / manpages-de-dev
h_errno.3.en	debian 11 / manpages-dev
h_errno.3.ja	debian 11 / manpages-ja-dev
h_errno.3.pl	debian 11 / manpages-pl-dev
h_errno.3.de	debian 12 / manpages-de-dev
h_errno.3.en	debian 12 / manpages-dev
h_errno.3.fr	debian 12 / manpages-fr-dev
h_errno.3.ja	debian 12 / manpages-ja-dev
h_errno.3.pl	debian 12 / manpages-pl-dev