Re: [bug-gawk] print statement problem with hexadecimal escape sequence

[Manuel Collado]

El 03/05/2018 a las 2:15, Hyunho Cho escribió:
> There is a erroneous print result with "\xHH" escape sequence that is 
> immediately followed by hexadecimal value (0-9a-f)

Not an erroneous result, but a problematic code:

$ awk --lint 'BEGIN { print "\x41\x42\x43FFF" }'  | od -a
awk: cmd. line:1: warning: POSIX does not allow `\x' escapes
awk: cmd. line:1: warning: hex escape \x43FFF of 5 characters probably 
not interpreted the way you expect
0000000   A   B del  nl
0000004

> $ gawk --version
> GNU Awk 4.1.4, API: 1.1 (GNU MPFR 3.1.6, GNU MP 6.1.2)
> Copyright (C) 1989, 1991-2016 Free Software Foundation.
>
> # there is no problem because "K" is not hex character.
>
> $awk 'BEGIN { print "\x41\x42\x43KKK" }'  | od -a
> 0000000   A   B   C   K   K   K  nl
> 0000007
>
> # There is a problem because "F" is hex character that immediately following 
> "\xHH" escape sequence.
>
> $ awk 'BEGIN { print "\x41\x42\x43FFF" }'  | od -a
> 0000000   A   B del  nl
> 0000004
>
> # if i insert a space in front of "F" then problem disappear.
>
> $ awk 'BEGIN { print "\x41\x42\x43 FFF" }' | od -a
> 0000000   A   B   C  sp   F   F   F  nl
> 0000010

Regards.
--
Manuel Collado - http://lml.ls.fi.upm.es/~mcollado