CVS commit: src/usr.bin/printf

["Robert Elz" <kre%netbsd.org@localhost>]

Module Name:    src
Committed By:   kre
Date:           Wed May 19 22:41:19 UTC 2021

Modified Files:
        src/usr.bin/printf: printf.c

Log Message:
Changes for POSIX conformance.

1.  exit(1) with an error message on stderr if an I/O error occurs.
1a. To work properly when built into /bin/sh sprinkle clearerr() at
    appropriate places.

2.  Verify that when a 'X data value is used with one of the numeric
    conversions, that nothing follows the 'X'.   It used to be unclear
    in the standard whether this was required or not, it is clear that
    with numeric conversions the entire data value must be used, or an
    error must result.   But with string conversions, that isn't the case
    and unused parts are simply ignored.   This one is a numeric conversion
    with a string value, so which applies?   The standard used to contain
    an example of '+3 being converted, producing the same as '+ ignoring
    the '3' with no mention of any error, so that's the approach we adopted,
    The forthcoming version now explicitly states that an error would also
    be generated from that case, as the '3' was not used by the numeric
    conversion.

2a. We support those conversions with floating as well as integer conversions,
    as the standard used to suggest that was required (but it makes no sense,
    the values are always integers, printing them in a floating format is
    dumb).  The standard has been revised to make it clear that only the
    integer numeric conversions %d %u %x (etc) are supposed to handle the 'X
    form of data value.   We still allow it with the floating formats as an
    extension, for backward compat, just in case someone (other than the ATF
    tests) is using it.   It might go away.

2b. These formats are sypposed to convert 'X where 'X' is a character
    (perhaps multibyte encoded) in the current LC_CTYPE locale category.
    We don't handle that, only 1 byte characters are handled currently.
    However the framework is now there to allow code to (one hopes, easily)
    be added to handle multi-byte locales.   (Note that for the purposes of
    #2 above, 'X' must be a single character, not a single byte.)


To generate a diff of this commit:
cvs rdiff -u -r1.52 -r1.53 src/usr.bin/printf/printf.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.