Hi guys. Have been working on a bit of a toy utility for myself to fill in a bit of downtime. Part of it involves interrogating a system, and dumping to screen a list of values, in column format.

A snippet of the code I'm using is shown below:

    my @UACS;
#    open(POLICY, "getpol -t UACS |"); commented - replaced by __DATA_
+_ for this example
    my $pol;
    while (<DATA>) # ($pol = <POLICY>) <== could this be changed to wh
+ile (my $pol = <POLICY>), to remove the previous line ??
    {
        chomp $_; # was $pol
        my($type,$number,$name);
        ($type, $number, $name) = split (/\|/, $_, -1);
        chomp $name;
        push(@UACS,$name);
    }
    @UACS = sort(@UACS);
    while (@UACS)
    {
        my @rows = splice(@UACS, 0, 6);
        printf "%-12s %-12s %-12s %-12s %-12s %-12s\n", @rows;
    }
    print "\nPress ENTER to continue...";
    my $a = <STDIN>;
#    close(POLICY); commented - superfluous due to __DATA__ for this e
+xample

__DATA__
UAC|10|ADMIN|Description1|
UAC|20|CIRC|Description2|
UAC|30|CIRCADMIN|Description3|
UAC|40|CIRCBEE|Description4|
UAC|50|CIRCBRO|Description5|
UAC|60|CIRCBUR|Description6|
UAC|70|CIRCBUW|Description7|
UAC|80|CIRCCAS|Description8|
UAC|90|CIRCCOM|Description9|

[download]

Now, whilst manipulating and testing the above to get it runnable for display here, I *may* have realised part of what the issue is... but there's still a ?? around part of it.

I'm thinking that, where the script is splitting the data, effectively, into rows of 6... when there aren't 6 items - as per the above example, on the second pass - it gives 3 instances of the "Use of uninitilized value in printf" error - which with this example equate to the 3 values that aren't there for the printf command on the second pass.

Sounds right so far, yeah? The only problem I have at this point, is that when running it with the full set of data, it gets around 90% of the way through, dumps out 4 of those errors, and then prints 2 more values at the end... which kind of blows my theory out of the water...

However - on having another look at the results, the 4 errors being spat out are after a "complete" line is printed, followed by the last 2 values. That equals 6 items, which is how many it's trying to print. Is printf somehow filling the %-12s from right to left for some reason, perhaps??

Please help me demistify this issue...

In reply to How to avoid "Use of uninitialized value" with printf? by bobdabuilda

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