Re: Getting the size of the call stack (efficiently)

Without knowing any magic, you could check at intervals other than 1.

my $depth = 1;
$depth *= 2 while ( caller $depth );
my $max = $depth - 1;
my $min = $depth / 2 + 1;
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Then do a binary search from there. You can probably get a bit faster if you know in advance about where your depth will be.

Update: Set starting depth to nonzero as suggested by Anno (though maybe 2 is a better value than 1 so that $depth / 2 + 1 is an integer).

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Re^2: Getting the size of the call stack (efficiently) by Anno (Deacon) on Feb 27, 2007 at 18:39 UTC
That looks promising (except the starting value for `$depth` should be nonzero :). Anno	[reply] [d/l]
Re^3: Getting the size of the call stack (efficiently) by kyle (Abbot) on Feb 27, 2007 at 18:44 UTC
Good catch! Fixed, thanks.	[reply]
Re^2: Getting the size of the call stack (efficiently) by Anno (Deacon) on Feb 27, 2007 at 20:37 UTC
Out of curiosity (and for the good purpose of delaying more serious work) I ran some bechmarks to find the break-even point of kyle's logarithmic method. I found it at a depth of 15 on my machine, frankly much lower than I expected but still a bit high for practical purposes. Calls don't often nest that deep. The relative efficiency varies from about 1:2 in favor of the linear method at depth 2 (the lowest that can be easily benchmarked), to, well, arbirtary much in favor of the logathithmic method. 1:3 at 100, 1:30 at 1000. The full story is a bit lengthy Read more... but here it is: (2 kB)	[reply] [d/l] [select]