zed.0xff.me

You MUST free memory you got from ALLOC_N & friends

It’s not documented anywhere, but you must call “xfree()” (note ‘x’ there) on memory blocks you got from ALLOC_N & friends.
Ruby will not free that memory automatically during it’s usual GC process.

Guys from ruby-talk and rubyforge also noticed that.

sample code:

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VALUE method_parse(VALUE self, VALUE text) {
    VALUE s;
    char *p    = RSTRING(text)->ptr;
    in_buf_len = RSTRING(text)->len;

    // [skipped some code here]

    buf = ALLOC_N(char, bufsize); 

    // protect buf from GC (theoretically)
    rb_iv_set(self,"@obj",Data_Wrap_Struct(rb_cData,NULL,NULL,buf));

    // [skipped some hard work here]

    // make ruby string from our char[] data
    s = rb_str_new(buf,bufptr-buf);

    // cleanup
    rb_iv_set(self,"@obj",Qnil);
    xfree(buf);
    buf  = NULL;
    bufsize = 0;

    return s;
}

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