```{index} single: s_isblk; Fcntl function ``` ```{index} single: Fcntl::s_isblk; Perl function ``` # s_isblk True if a stat-mode value names a block-special device. ## Synopsis ```perl my $mode = (stat "/dev/sda")[2]; print "block device\n" if S_ISBLK($mode); ``` Returns `1` when `$mode & S_IFMT == S_IFBLK`, `0` otherwise. With no argument, returns `0`.