Ceiling to the nearest ten?

R-users,

Is there a function for ceiling to the nearest ten?

a <- 1:10*4
a
[1]  4  8 12 16 20 24 28 32 36 40

The resulting vector should look like this ("ceiling to the nearest ten")
[1] 10 10 20 20 20 30 30 40 40 40

Thanks in advance
Lauri