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unsigned long long integers

2 messages · robin hankin, Brian Ripley

Original
robin hankin
# 
Hi.

R-exts, section 1.7, discusses the passing of long long integers  
between R and C.
I want to use unsigned long long integers, but
I only need them inside a C function.

I have a  function that maps the nonnegative integers to the positive  
integers.
The function is defined by a delicate recursive algorithm that is exact
for integer arithmetic, but wildly incorrect for doubles.

The function increases rapidly with its argument, and ordinary integers
are not enough to illustrate my point (in a paper I am writing).


The C function is as follows:



void numbparts_longint(int *n, double *p){/* p(1)...p(n) calculated */
         int i,s,f,r;
         unsigned long long int *ip;
         unsigned long long int pp[*n];

/* COMPLICATED RECURSIVE ALGORITHM IN WHICH PP IS FILLED SNIPPED */

         for(i=0 ; i < *n ; i++){
                 p[i] = (double) pp[i];
         }
}



This compiles fine with "gcc -Wall" (and illustrates my point!)
but R CMD check reports


   partitions.c:180: warning: ISO C90 does not support 'long long'
   partitions.c:181: warning: ISO C90 does not support 'long long'


I really want long long integers here.  What are my options?
[the same happens with signed long long integers]





--
Robin Hankin
Uncertainty Analyst
National Oceanography Centre, Southampton
European Way, Southampton SO14 3ZH, UK
  tel  023-8059-7743
Brian Ripley
# 
R-admin recommends -std=gnu99, which will solve this.

Given that long and long long mean different things on different 
platforms, I would endorse the recommendation to use a C99 explicit type.
On Mon, 24 Apr 2006, Robin Hankin wrote: