Diff between 'print POSIX::cuserid' and 'use POSIX; print cuserid'

wsanders has asked for the wisdom of the Perl Monks concerning the following question:

cuserid() is supposed to return the name of the user associated with the EUID of the process. I have a shell: I logged in as "wsanders", then "su - adudaren". Both my EUID and UID are the number associated with 'adudaren'. However, cuserid() gives me different results:

1) perl -e 'use POSIX; print cuserid'
wsanders

2) perl -e 'print POSIX::cuserid'
adudaren
[download]

I would expect cuserid to return "adudaren" no matter how I call it, it's getlogin() that returns the name of the user associated with the controlling terminal (the original logger-inner.) What's the difference between 1 and 2? Thanks, -w (there, that's better)

Comment on Diff between 'print POSIX::cuserid' and 'use POSIX; print cuserid' Download Code

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Re: Diff between 'print POSIX::cuserid' and 'use POSIX; print cuserid' by linuxer (Curate) on Jan 08, 2013 at 00:10 UTC
In your first example, you did a `use POSIX`; in the second, you did not. Why? Without loading `POSIX` you won't be able to call a function like `POSIX::cuserid`. Enable ~~`strict`~~warnings and see yourself what happens: `$ perl -wE 'say POSIX::cuserid' Name "POSIX::cuserid" used only once: possible typo at -e line 1. say() on unopened filehandle cuserid at -e line 1.` [download] But with loading POSIX: `$ perl -MPOSIX -wE 'say POSIX::cuserid' linuxer` [download] Updates replaced strict with warnings; removed strict from code examples; the warning is the crucial part.	[reply] [d/l] [select]
Re^2: Diff between 'print POSIX::cuserid' and 'use POSIX; print cuserid' by wsanders (Novice) on Jan 08, 2013 at 21:10 UTC
Thanks, yes, so in #2 POSIX isn't loaded, so perl -e 'print POSIX::cuserid' should return nothing, actually. That's the answer. There is something odd about this user's environment that is causing it to print his username. In my environment, and root's, it behaves the way it is supposed to. Not going to investigate further.	[reply]
Re: Diff between 'print POSIX::cuserid' and 'use POSIX; print cuserid' by choroba (Cardinal) on Jan 08, 2013 at 01:00 UTC
Please, fix the problems indicated by others. Note that cuserid and `$>` both reflect changes made from within the script: `$ sudo perl -MPOSIX - $UID print cuserid, " $< $>\n"; $> = shift; print cuserid, " $< $>\n"; __END__` [download] لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l] [select]
Re: Diff between 'print POSIX::cuserid' and 'use POSIX; print cuserid' by LanX (Saint) on Jan 07, 2013 at 23:49 UTC
I think I can spot a difference ... but before you reformat your post with code-tags I'm not sure enough to tell. ;-) UPDATE: yeah better! =) `> perl -we 'print POSIX::cuserid' Name "POSIX::cuserid" used only once: possible typo at -e line 1. print() on unopened filehandle cuserid at -e line 1. > perl -we 'use POSIX;print POSIX::cuserid' lanx` [download] So what happens if you also `use POSIX`? Cheers Rolf	[reply] [d/l] [select]