Easiest way to access rb_sprintf

Ruby
1

Hi

I want to create a ruby method in a C++ extension that will spit out the
C++ pointer address of the wrapped object - useful for debugging. I
have got the following, which works, but I was wondering if there was an
easier way to access this that I’m missing?

static VALUE
cpp_ptr_addr(VALUE self, VALUE obj)
{
size_t ptr = (size_t)DATA_PTR(obj);
return rb_funcall( rb_mKernel, rb_intern(“sprintf”), 2,
rb_str_new2(“0x%x”), OFFT2NUM(ptr) );
}

thanks
alex

2

Alex F. wrote:

Hi

I want to create a ruby method in a C++ extension that will spit out the
C++ pointer address of the wrapped object - useful for debugging. I
have got the following, which works, but I was wondering if there was an
easier way to access this that I’m missing?

static VALUE
cpp_ptr_addr(VALUE self, VALUE obj)
{
size_t ptr = (size_t)DATA_PTR(obj);
return rb_funcall( rb_mKernel, rb_intern(“sprintf”), 2,
rb_str_new2(“0x%x”), OFFT2NUM(ptr) );
}

thanks
alex

Instead of calling Ruby’s sprintf, use C’s standard sprintf with the %p
conversion specifier, then convert the result to a Ruby string.

3

Hi,

At Mon, 18 Aug 2008 22:31:41 +0900,
Alex F. wrote in [ruby-talk:311670]:

I want to create a ruby method in a C++ extension that will spit out the
C++ pointer address of the wrapped object - useful for debugging. I
have got the following, which works, but I was wondering if there was an
easier way to access this that I’m missing?

rb_sprintf is a function added in 1.9, and you can use it like
printf.

static VALUE
cpp_ptr_addr(VALUE self, VALUE obj)
{
void *ptr = DATA_PTR(obj);
return rb_sprintf("%p", ptr);

4

Nobuyoshi N. wrote:

static VALUE
cpp_ptr_addr(VALUE self, VALUE obj)
{
void *ptr = DATA_PTR(obj);
return rb_sprintf("%p", ptr);
}

excellent, thank you both. i’m ultimately targetting 1.9 so this is
ideal.

alex