607. Concern about short seed vectors

Section: 29.6.7.1 [rand.util.seedseq] Status: CD1 Submitter: Charles Karney Opened: 2006-10-26 Last modified: 2016-02-10

Priority: Not Prioritized

View all other issues in [rand.util.seedseq].

View all issues with CD1 status.

Discussion:

Short seed vectors of 32-bit quantities all result in different states. However this is not true of seed vectors of 16-bit (or smaller) quantities. For example these two seeds

unsigned short seed = {1, 2, 3};
unsigned short seed = {1, 2, 3, 0};

both pack to

unsigned seed = {0x20001, 0x3};

yielding the same state.

See N2391 and N2423 for some further discussion.

Proposed resolution:

Adopt the proposed resolution in N2423.

[ Kona (2007): The LWG adopted the proposed resolution of N2423 for this issue. The LWG voted to accelerate this issue to Ready status to be voted into the WP at Kona. ]