Re: printf hex conversion gives wrong values

[Bob Proulx]

> > during developing a new shell script; I detected an erroneous behaviour
> > of the printf command.
> > printf fails on hex conversion for 008 and 009 and gives wrong values
> > for higher numbers, if the digit to convert contains leading zeroes.
> > Without leading zeroes the conversion succeeds.
> 
> I'm guessing that 'printf' is interpretting the number as an octal number,
> because of the leading zeroes. I can't seem to find anything in 'man printf'
> or 'info printf' to confirm this, though (DJGPP port of sh-utils 2.0.11).

I did not see it documented in the 'info printf' documentation
either.  But the standards require it.

  http://www.unix-systems.org/single_unix_specification_v2/xcu/printf.html

    Note that the value shown on standard output is what would be
    expected as the return value from the XSH specification function
    strtol(). A similar correspondence exists between %u and strtoul()
    and %e, %f and %g (if the implementation supports floating-point
    conversions) and %strtod().

And tracing through to the strtoul() docs:

  http://www.unix-systems.org/single_unix_specification_v2/xsh/strtol.html

    If the value of base is 0, the expected form of the subject
    sequence is that of a decimal constant, octal constant or
    hexadecimal constant, any of which may be preceded by a + or -
    sign. A decimal constant begins with a non-zero digit, and
    consists of a sequence of decimal digits. An octal constant
    consists of the prefix 0 optionally followed by a sequence of the
    digits 0 to 7 only. A hexadecimal constant consists of the prefix
    0x or 0X followed by a sequence of the decimal digits and letters
    a (or A) to f (or F) with values 10 to 15 respectively.

Bob