[Rd] Compile warning in unique.c

Thomas Lumley tlumley at u.washington.edu
Mon Aug 29 16:37:08 CEST 2005

On Mon, 29 Aug 2005, Harris, Michael (NIH/NCI) [E] wrote:
> I am getting a compile warning when building R from source.  I am building
> on a AMD64 Opteron system  with  gcc (GCC) 3.3.3 (SuSE Linux)
> The warning is:
>            unique.c: In function `cshash':
> unique.c:1146: warning: cast from pointer to integer of different size

The comment immediately above this suggests that it is deliberate

  /* Use hashing to improve object.size. Here we want equal CHARSXPs,
     not equal contents.  This only uses the bottom 32 bits of the pointer,
     but for now that's almost certainly OK */

The warning is presumably because casting this int back to a pointer would 
fail (and is a common 32 to 64bit conversion error), but that's not what 
is happening here.


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