Man pages matching name gfs_pio_sendfile in section 3:

gfs_pio_sendfile.3.en	debian 10 / libgfarm-dev
gfs_pio_sendfile.3.ja	debian 10 / libgfarm-dev
gfs_pio_sendfile.3.en	debian 11 / libgfarm-dev
gfs_pio_sendfile.3.ja	debian 11 / libgfarm-dev
gfs_pio_sendfile.3.en	debian 12 / libgfarm-dev
gfs_pio_sendfile.3.ja	debian 12 / libgfarm-dev