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Postings from February 2017
On Thu, Feb 9, 2017 at 1:29 AM, Karl Williamson <public@khwilliamson.com> wrote: > It looks to me, and others on #p5p that there are 4 unused bits in the > flags for an SV. > > The types take up 4 bits, but then the actual flags, like SVf_IOK, start > at 0x100. That apparently means bits matching the mask 0xF0 are > available. Are we wrong? > "He guessed as well as he could, and crawled along for a good way, till suddenly his hand met what felt like a tiny ring of cold metal lying on the floor of the tunnel. It was a turning point in his career, but he did not know it. He put the ring in his pocket almost without thinking; certainly it did not seem of any particular use at the moment." - Riddles in the Dark - The Hobbit The other bits are actually used in one condition: to mark the SV as freed SvTYPE is set to 0xFF. Other than that, the bits are indeed unused. They're probably the most precious bits we have in perl, given that everyone wants flag bits for their favorite feature. LeonThread Previous | Thread Next