Creating new Ruby strings in C

ruby-talk
1

Some questions about the rb_str_new…rb_str_new5 functions.
Is it possible for RSTRING(str)->ptr to reference a C string or part of a
C buffer with out eventually calling free on ptr (and without stopping
the gc)?
I imagine the gc will eventually call free on ptr for any Ruby string
created with rb_str_new2.
What are str_new3 and str_new4 used for?
Thanks in advance,
Charlie

2

Is it possible for RSTRING(str)->ptr to reference a C string or part of a
C buffer with out eventually calling free on ptr (and without stopping
the gc)?

yes, and no : see mmap

mmap can be seen as a delegator : in some case, it just create a String
object and call the corresponding String method, but it's very carefull
about the gc

What are str_new3 and str_new4 used for?

shared string used for example in string and regexp. Just an example with
regexp

   a = "aaa"
   /.*/ =~ a
   a << "b"

After the match, $~ and `a' "share" internally the same string, but the
variable `a' is marked "copy-on-write". When ruby want to modify `a', it
first duplicate the string and make the modification.

Guy Decoux

3

shared string used for example in string and regexp. Just an example with

                                      ^^^^^^
                                       hash

regexp

sorry,

Guy Decoux