$ perle 'use Fcntl; use constant F_NOCACHE => 48; say O_RDONLY; say F_NOCACHE'
0
48

$ perle 'use Fcntl; use constant F_NOCACHE => 48; say O_RDONLY | F_NOCACHE'
48

$ perle 'use Fcntl; use enum qw{F_NOCACHE=48}; say O_RDONLY; say F_NOCACHE'
0
48

$ perle 'use Fcntl; use enum qw{F_NOCACHE=48}; say O_RDONLY | F_NOCACHE'
48