UNIX for Advanced & Expert Users

The old SysV Unix /bin/oawk and /bin/nawk have the same limit:

Code:

echo 2147483649 | /bin/oawk '{printf "%d\n", $1}'
2147483647
echo 2147483649 | /bin/nawk '{printf "%d\n", $1}'
2147483647

While print has a higher limit

Code:

echo 2147483649 | /bin/oawk '{print $1}'
2147483649
echo 2147483649 | /bin/nawk '{print $1}'
2147483649

@MadeinGermany, the latter is because the numbers are interpreted as a string:

Code:

$ echo 214744445564646464646454646646464646466666646456456546456456466464646483649 | awk '{print $1}'
214744445564646464646454646646464646466666646456456546456456466464646483649

Oh I overlooked that, have to force a number:

Code:

echo 2147483649 | /bin/oawk '{print $1+0}'
2147483649
echo 2147483649 | /bin/nawk '{print $1+0}'
2147483649

Interesting: GNU awk immediately escapes to floating point here.

What I think the standard says (whether or not it matters, is another matter).

POSIX mandates doubles for all AWK numerics [1]:
So, at least at the outset, the valid integral range is approximately -2^53 to 2^53.

What should happen when you try to print the integer using printf "%d" bigint? POSIX AWK says [1]:
The File Format Notation [2] section then says:
Note the use of "integer", not "int" as is the case in the C library implementation. The latter is a specific data type, the former is not. In this context, what exactly is an "integer"?

In Concepts Derived from the ISO C Standard [3], POSIX says:
So, it seems to me that POSIX requires compliant AWK implementations to store all values as doubles and to use at least signed long when converting an integral double to an integral type.

If this is correct, a compliant AWK implementation on an LP64 platform (most 64-bit UNIX) should never lose precision when converting a double to an integer.

I know that nawk does indeed store all numerics as doubles. However, it casts to signed int during printf "%d" ....

References:
[1] POSIX: AWK
[2] POSIX: File Format Notation
[3] POSIX: Concepts Derived from the ISO C Standard

Regards,
Alister

Interesting, and neither mawk (typical versions) nor nawk are POSIX compliant. Case in point on Solaris:

Code:

$ echo 2147483649 | /bin/nawk '{printf "%d\n", $1}'
2147483647
$ echo 2147483649 | /usr/xpg4/bin/awk '{printf "%d\n", $1}'
2147483649