[fpc-devel] I get duplicate GUIDs under Linux

[Graeme Geldenhuys]

2008/5/29 Florian Klaempfl <florian at freepascal.org>:
>> How do I know if it's using Random or '/proc/sys/kernel/random/uuid'?
>> Browsing the RTL source code with Lazarus, I believe I am using the
>> latter, but not 100% sure.
>
> If it uses /proc/sys/kernel/random/uuid, strace shows it.

Thanks Florian.  I am using the '.../random/uuid'.

nanosleep({0, 700000000}, {3082747920, 3219878756}) = 0
open("/proc/sys/kernel/random/uuid", O_RDONLY|O_LARGEFILE) = 872
read(872, "2c4bd506-c58f-4b6d-b88c-eec01a05"..., 36) = 36
ioctl(3, FIONREAD, [0])                 = 0
nanosleep({0, 700000000}, {3082747920, 3219878756}) = 0
open("/proc/sys/kernel/random/uuid", O_RDONLY|O_LARGEFILE) = 873
read(873, "ea14fbdc-8d6b-45de-ae7a-5e6e1908"..., 36) = 36
ioctl(3, FIONREAD, [0])                 = 0
nanosleep({0, 700000000},  <unfinished ...>
Process 6582 detached


I'm not putting a 700ms sleep between each CreateGUID call, to see
what happens. I noticed that once I hit the 1021 limit at normal speed
(no sleep). Every time I click the button quickly (2-3 times per
second) it instantly generates the same GUID. If I wait a second
between clicks, I get a duplicate on the 2nd add to stringlist. Weird,
but then, I got no idea what this will prove!  :-)


Regards,
 - Graeme -


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