Where does L come from?
On 08/25/2018 02:23 PM, Dirk Eddelbuettel wrote:
On 25 August 2018 at 13:49, Herv? Pag?s 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)")
[1] 8
R> Rcpp::evalCpp("sizeof(int)")
[1] 4
R>
My bad, it's only the same on Windows. My point is that the discussion about the size of int vs long int is only a distraction here. The important bit is that 10L in R is represented by 10 in C, which is an int, not by 10L, which is a long int. Could hardly be more confusing. H.
Dirk | H. | | 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 | > | | -- | Herv? Pag?s | | Program in Computational Biology | Division of Public Health Sciences | Fred Hutchinson Cancer Research Center | 1100 Fairview Ave. N, M1-B514 | P.O. Box 19024 | Seattle, WA 98109-1024 | | E-mail: hpages at fredhutch.org | Phone: (206) 667-5791 | Fax: (206) 667-1319
Herv? Pag?s Program in Computational Biology Division of Public Health Sciences Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N, M1-B514 P.O. Box 19024 Seattle, WA 98109-1024 E-mail: hpages at fredhutch.org Phone: (206) 667-5791 Fax: (206) 667-1319