Not knowing much C, I was confused about why malloc() wouldn't get called for th...

metageek · on Jan 4, 2012

Even if you're not putting the RString struct on the stack, the embedded string optimization means calling malloc() just once instead of twice.

ori_b · on Jan 4, 2012

You can allocate the string with one malloc:

    RString *s = malloc(sizeof(RString) + length); /* allocate 'length' bytes extra memory past the end of 's' */
    s->data = s + 1; /* to the extra memory past the start of the string struct */

teaspoon · on Jan 4, 2012

Ruby strings are mutable, so you need to be able to free s->data without freeing the RString itself.

ori_b · on Jan 5, 2012

    s = realloc(s, sizeof(RString));

haileys · on Jan 5, 2012

MRI objects are not relocatable so that won't work if realloc has to move the structure in memory

dchest · on Jan 4, 2012

Nitpick: sizeof(RString) + length may overflow size_t.