On Wed, 13 Nov 2024 at 11:38, Alejandro Colomar <alx@xxxxxxxxxx> wrote: > > Hi Ken, > > On Wed, Nov 13, 2024 at 02:11:52AM GMT, Ken Pizzini wrote: > > The description of the %a/%A specifiers in the printf(3) man page > > could stand some improvement. In particular, it is not clear from > > the current (6.9.1) document what base is used for the "p±d" part of > > the format. Furthermore, the description refers to a "decimal point", > > even though it would be better referred to as the "radix point", > > as the number in question is not a decimal representation. > > > > It can be inferred from the nature of %a that the base should be > > a power of two. and it can be further inferred from the nature of > > hexadecimal floating-point literals in C (as specified by C99 and > > later) that the base must exactly be the number two, but it would be > > helpful for the printf(3) man page to state this explicitly. My first > > expectation when reading the man page was that the exponent would be > > taken in base 16; my second thought is that it is base FLT_RADIX (which > > is 2 on IEEE 754 floating-point systems, but 16 on S/390). Only by > > going back to the standard and reading carefully could I determine > > that the exponent in p-notation must always be taken from a base of 2. > > > > A patch with one suggested wording is attached. The entry for "a, A" in > > https://pubs.opengroup.org/onlinepubs/9699919799/functions/printf.html > > The latest standard is POSIX.1-2024. Please link to it. > > <https://pubs.opengroup.org/onlinepubs/9799919799/functions/printf.html> > > > gives an even better rewording, though I suspect there would be > > copyright issues in simply copying its text. > > > > --Ken Pizzini > > > The patch is missing the metadata that will make it be accepted by > git-am(1). Would you mind formatting the patch with > git-format-patch(1)? > > See: > <https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING.d/patches/patches> > <https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING.d/patches/description> > <https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING.d/patches/subject> > > > --- printf.3~ 2024-11-13 01:07:23.023847047 -0800 > > +++ printf.3 2024-11-13 01:55:48.368341811 -0800 > > @@ -757,15 +757,18 @@ > > the letters ABCDEF, and the exponent separator > > .B P > > is used. > > -There is one hexadecimal digit before the decimal point, > > +There is one hexadecimal digit before the radix point, > > and the number of digits after it is equal to the precision. > > The default precision suffices for an exact representation of the value > > if an exact representation in base 2 exists > > and otherwise is sufficiently large to distinguish values of type > > .IR double . > > -The digit before the decimal point is unspecified for nonnormalized > > +The digit before the radix point is unspecified for nonnormalized > > numbers, and nonzero but otherwise unspecified for normalized numbers. > > -The exponent always contains at least one > > +The exponent > > +.IR d , If there's a comma after d then shouldn't there be one before it too? So either "The exponent, d, is ..." or just "The exponent d is ..." But not "The exponent d, is ..." > > +which is the appropriate exponent of 2 expressed as a decimal integer, > > I would remove the 'which', and s/,/;/ > > > +always contains at least one > > And prepend an 'it' here. > > Other than that, it LGTM. Thanks! > > Have a lovely day! > Alex > > > digit; if the value is zero, the exponent is 0. > > .TP > > .B c > > > -- > <https://www.alejandro-colomar.es/>
