crypt prototype and ( time ) x 2

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Re: crypt prototype and ( time ) x 2 by liz (Monsignor) on Oct 08, 2003 at 09:15 UTC
To me this falls in the category: Q: Doctor, it hurts when I press here A: Then don't press there! How about `crypt( time,time )`, or probably better: `my $time; crypt( $time = time,$time );` [download] Liz Update: Moved lexical outside of crypt(), as second $time would be undef because it would refer to a non-existing global $time (which shows nicely when using strict). Thanks to broquaint for pointing this out.	[reply] [d/l] [select]
Re: crypt prototype and ( time ) x 2 by Abigail-II (Bishop) on Oct 08, 2003 at 09:49 UTC
Either do what Liz said, or if you really don't want to create extra variables, do something like: `$ perl -wle 'print sub {crypt $_ [0], $_ [0]} -> (time)'` [download] Having said that, one should realize that the output only changes every 100 seconds, as crypt only looks at the first 8 characters, and time returns nowadays a 10 digit number. Abigail	[reply] [d/l]
•Re: Re: crypt prototype and ( time ) x 2 by merlyn (Sage) on Oct 08, 2003 at 14:20 UTC
`$ perl -wle 'print sub {crypt $_ [0], $_ [0]} -> (time)'` [download] Or, more simply: `$ perl -wle 'print crypt($_, $_) for time;'` [download] -- Randal L. Schwartz, Perl hacker Be sure to read my standard disclaimer if this is a reply.	[reply] [d/l] [select]
Re: Re: crypt prototype and ( time ) x 2 by DentArthurDent (Monk) on Oct 08, 2003 at 13:01 UTC
If you wanted to get around the time only changing every 100 seconds problem use: `$time = time() % 100000000; # time mod a number with 8 zeros` [download] That will give you a different time-seeded number every second, being the last 8 digits of the time returned by the time function. ---- If I melt dry ice can I swim without getting wet?	[reply] [d/l]
Re: crypt prototype and ( time ) x 2 by broquaint (Abbot) on Oct 08, 2003 at 09:47 UTC
but get Undefined subroutine &main::crypt This is because prepending subroutines with an ampersand forces a user defined function to be called. If you're really determined to override the default prototype, you could just subvert `crypt` with the `subs` module e.g `use subs 'crypt'; sub crypt { CORE::crypt($_[0], $_[1]) } print crypt( (time) x 2 );` [download] For a good rant^Warticle on prototypes in perl see Tom Christiansen's FMTEYEWTK about Prototypes in Perl. HTH `_________ broquaint`	[reply] [d/l]
Re: crypt prototype and ( time ) x 2 by MidLifeXis (Monsignor) on Oct 08, 2003 at 17:21 UTC
This response does not answer the question directly, but asks the AM to evaluate what is trying to be accomplished. You will not get the randomness in your seed that you are expecting. Your seed will always be '10' (at least for the next ~ 34000000 seconds). Even if you use DentArthurDent's suggestion, you are still only using 100 out of 6464 possible salts, because you are ignoring 54 (I think) other valid characters which can randomize the salt. To randomize the salt a little more, you may want to use some form of pack to convert time() into a base64 string, and use that as your salt. Update:* Fixed DentArthurDent's name. Sorry :) Update-2: Fixed Speelink mesteaks.	[reply]
Re: crypt prototype and ( time ) x 2 by ambrus (Abbot) on Oct 10, 2003 at 11:11 UTC
The problem is, that crypt has a prototype ($$). I've met this problem with select: I tried to write `select +(undef)x3, 0.4;` but that won't work for exactly the same reason. As a solution, you can write a wrapper function: `sub cryp{crypt$_[0],$_[1]};cryp +(time)x2;`	[reply] [d/l] [select]