[Rd] names<- appears to copy 3 times?

[Matthew Dowle]

Hi,

$ R --vanilla
R version 2.14.1 (2011-12-22)
Platform: i686-pc-linux-gnu (32-bit)
> DF = data.frame(a=1:3,b=4:6)
> DF
  a b
1 1 4
2 2 5
3 3 6
> tracemem(DF)
[1] "<0x8898098>"
> names(DF)[2]="B"
tracemem[0x8898098 -> 0x8763e18]: 
tracemem[0x8763e18 -> 0x8766be8]: 
tracemem[0x8766be8 -> 0x8766b68]: 
> DF
  a B
1 1 4
2 2 5
3 3 6
> 

Are those 3 copies really taking place? 

Matthew