[Rd] Where does L come from?
edd @ending from debi@n@org
Sat Aug 25 23:23:36 CEST 2018
On 25 August 2018 at 13:49, Hervé Pagès wrote:
| The choice of the L suffix in R to mean "R integer type", which
| is mapped to the "int" type at the C level, and NOT to the "long int"
| type, is really unfortunate as it seems to be misleading and confusing
| a lot of people.
The point I was trying to make in what you quote below is that the L may come
from a time when int and long int were in fact the same on most relevant
architectures. And it is hardly R's fault that C was allowed to change.
Also, it hardly matters given that R has precisely one integer type so I am
unsure where you see the confusion between long int and int.
| The fact that nowadays "int" and "long int" have the same size on most
| platforms is only anecdotal here.
| Just my 2 cents.
Are you sure?
R> Rcpp::evalCpp("sizeof(long int)")
| On 08/25/2018 10:01 AM, Dirk Eddelbuettel wrote:
| > On 25 August 2018 at 09:28, Carl Boettiger wrote:
| > | I always thought it meant "Long" (I'm assuming R's integers are long
| > | integers in C sense (iirrc one can declare 'long x', and it being common to
| > | refer to integers as "longs" in the same way we use "doubles" to mean
| > | double precision floating point). But pure speculation on my part, so I'm
| > | curious!
| > It does per my copy (dated 1990 !!) of the 2nd ed of Kernighan & Ritchie. It
| > explicitly mentions (sec 2.2) that 'int' may be 16 or 32 bits, and 'long' is
| > 32 bit; and (in sec 2.3) introduces the I, U, and L labels for constants. So
| > "back then when" 32 bit was indeed long. And as R uses 32 bit integers ...
| > (It is all murky because the size is an implementation detail and later
| > "essentially everybody" moved to 32 bit integers and 64 bit longs as the 64
| > bit architectures became prevalent. Which is why when it matters one should
| > really use more explicit types like int32_t or int64_t.)
| > Dirk
| Hervé Pagès
| Program in Computational Biology
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