Man pages matching name isinf in section 3:

isinf.3.en	debian 10 / manpages-dev
isinf.3.es	debian 10 / manpages-es
isinf.3.ja	debian 10 / manpages-ja-dev
isinf.3.pl	debian 10 / manpages-pl-dev
isinf.3.pt	debian 10 / manpages-pt-dev
isinf.3.en	debian 11 / manpages-dev
isinf.3.fr	debian 11 / manpages-fr-dev
isinf.3.ja	debian 11 / manpages-ja-dev
isinf.3.pl	debian 11 / manpages-pl-dev
isinf.3.pt	debian 11 / manpages-pt-dev
isinf.3.en	debian 12 / manpages-dev
isinf.3.fr	debian 12 / manpages-fr-dev
isinf.3.ja	debian 12 / manpages-ja-dev
isinf.3.pl	debian 12 / manpages-pl-dev
isinf.3.ru	debian 12 / manpages-ru-dev