Re: [pure-lang-users] C float

[Eddie R. <er...@bm...>]

On Wed, 2008-08-13 at 11:16 -0400, John Cowan wrote:
> Eddie Rucker scripsit:
> 
> > Thanks. What about const and unsigned parameters?
> 
> Casting away const is always safe: const essentially documents how the callee
> uses the argument or its referent.

Ok. I understand this one.

> Unsigned does need explicit support to consistently get the right results:
> in particular, a too-big unsigned value should become a bignum.

Hmm. I didn't even think about big numbers. I was worried about the
following scenario:

Some C library called f2.so defined by:

unsigned int foo(unsigned int a) {
  return a + 1;
}

Then from Pure:
 > using "lib:/t2.so";
 > extern int foo(int);
 > let a = 2147483646;
 > foo (a div -1);
 -2147483645

Now, the following C program gives different results:

#include <stdio.h>

unsigned int foo(unsigned int a) {
  return a + 1;
}

int main() {
  unsigned int a = 2147483646;

  printf("%d\n", foo(a/-1));

  return 0;
}

Results:
 :~$ ./a.out
 1

e.r.