Man pages matching name setbuf in section 3:

setbuf.3.de	debian 10 / manpages-de-dev
setbuf.3.en	debian 10 / manpages-dev
setbuf.3.es	debian 10 / manpages-es
setbuf.3.ja	debian 10 / manpages-ja-dev
setbuf.3.pt	debian 10 / manpages-pt-dev
setbuf.3.zh_CN	debian 10 / manpages-zh
setbuf.3.zh_TW	debian 10 / manpages-zh
setbuf.3.de	debian 11 / manpages-de-dev
setbuf.3.en	debian 11 / manpages-dev
setbuf.3.es	debian 11 / manpages-es-dev
setbuf.3.fr	debian 11 / manpages-fr-dev
setbuf.3.ja	debian 11 / manpages-ja-dev
setbuf.3.pt	debian 11 / manpages-pt-dev
setbuf.3.zh_CN	debian 11 / manpages-zh
setbuf.3.zh_TW	debian 11 / manpages-zh
setbuf.3.de	debian 12 / manpages-de-dev
setbuf.3.en	debian 12 / manpages-dev
setbuf.3.ja	debian 12 / manpages-ja-dev
setbuf.3.zh_CN	debian 12 / manpages-zh
setbuf.3.zh_TW	debian 12 / manpages-zh