perl - sprintf : fixed point, big numbers and precision loss -


i need read numbers in database , write them text file using perl.

in table numbers, data format defined numeric (25,5) (it reads 25 digits, including 5 decimals).

i format numbers in file sprintf "%.5f", $myvalue force 5 decimals , noticed greats values, there precision loss numbers more 17 digits :

db   = 123.12345 file = 123.12345 (ok)  db   = 12345678901234891.12345 file = 12345678901234892.00000 (seems rounded upper integer)  db   = 12345678901234567890.12345 file = 12345678901234567000.00000 (truncation ?)

what perl's greatest precision fixed decimal numbers?

i aware of concepts , limitations of floating point arithmetic in general, not perl monk , not know internals of perl don't know if normal (or if related @ floating point). not sure either if internal limitation of perl, or problem related sprintf processing.

is there workaround or dedicated module problem?

some notable points :

  • this additional feature of system uses perl, using tool not option
  • the data being crunched financial need keep every cent , cannot cope +/- 10 000 units precision :^s

once again, finding solution right after asking so. putting solution here, future visitor :

replace 

$myout = sprintf "%.5f", $myvalue;

by 

use math::bigfloat; $myout = math::bigfloat->new($myvalue)->ffround( -5 )->bstr;

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