Re: [bug-gawk] Awk cannot properly deal with too small numbers.

[arnold]

Hi.

Thanks for the bug report.

Zhengyu Guo <address@hidden> wrote:

> Hi,
>
> I encountered a problem when dealing with very small numbers. The test case
> this shown below
>
> ~~~
> $ echo 1.1e-307 | awk '$1<0.05{print}'
> 1.1e-307
> $ echo 1.1e-309 | awk '$1<0.05{print}’
> ~~~
>
> Both commands should print out the input number. However, the second
> command print out nothing.
>
> It seems that when the numeric number is too small, AWK cannot process it
> correctly.

There are two things interacting here.

First, awk (and gawk) are limited by the capabilities of hardware
double precision floating point, and the second number is too small
to be represented numerically.

Once that's true, $1 is treated just as a string, and the string comparison

        "1.1e-309" < "0.05"

fails.

There isn't much else to do.

Thanks,

Arnold