[CExt] C array to Ruby Array?

[thomthom]

Say you have a C array, int carr[10]; or double carr[10];.
Is there a single method to convert the C array to a Ruby array?

Or does one have to create a Ruby array, iterate the C array and populate one value at a time?

[MartinRinehart]

Ruby has its wonderful numbers (integers when possible, floats as needed) but they aren't C's much simpler (and faster) plain numbers. Cs numbers can be used directly by the CPU/FPU. Ruby's numbers are object instances.

[thomthom]

I am writing a Ruby C Extension. What I tried to hint by [CExt].

TDB let me know I need to do the latter in order to convert C arrays to Ruby arrays.

[AdamB]

Generally No, because the underlying representations are different. (eg Integer in Ruby is actually an integer times 4)

Doubles are the exception as the representation in C and Ruby are the same IEEE format.

So the values can simply be copied. However the container is another matter; in C, arrays are little more than syntactic sugar, in Ruby an Array is a real live object, so you're kinda out luck.

The best you could do would be something like:

extern double *reals
extern int rcount;

static VALUE
method_getRealArray(VALUE rarray)
{
  if (rcount < RARRAY_LEN(rarray))
  {
    memcpy(RARRAY_PTR(rarray), reals, sizeof(double)* rcount);  
    return Qtrue;
 }
  else
  {
    return Qfalse;
  } 
}