missing verr/vwarn functions

This bug is carved off from bug 3403.

LSB function verrx is part of a set of interfaces, only some of which are
included. From glibc err.h (annotated)

LSB: extern void warn (__const char *__format, ...)
     __attribute__ ((__format__ (__printf__, 1, 2)));
NO: extern void vwarn (__const char *__format, __gnuc_va_list)
     __attribute__ ((__format__ (__printf__, 1, 0)));

/* Likewise, but without ": " and the standard error string. */
LSB: extern void warnx (__const char *__format, ...)
     __attribute__ ((__format__ (__printf__, 1, 2)));
NO: extern void vwarnx (__const char *__format, __gnuc_va_list)
     __attribute__ ((__format__ (__printf__, 1, 0)));

/* Likewise, and then exit with STATUS. */
LSB: extern void err (int __status, __const char *__format, ...)
     __attribute__ ((__noreturn__, __format__ (__printf__, 2, 3)));
NO: extern void verr (int __status, __const char *__format, __gnuc_va_list)
     __attribute__ ((__noreturn__, __format__ (__printf__, 2, 0)));
LSB: extern void errx (int __status, __const char *__format, ...)
     __attribute__ ((__noreturn__, __format__ (__printf__, 2, 3)));
LSB: extern void verrx (int __status, __const char *, __gnuc_va_list)
     __attribute__ ((__noreturn__, __format__ (__printf__, 2, 0)));

So verrx is the only one of the four 'v' forms that is marked as included.
This whole family of eight is described by the Linux manpage as "nonstandard
BSD extensions"

In bug 3403 it was decided to do nothing but fix the incorrect details of verrx
during the bug-fix cycle; this bug tracks the resolution of the whole issue -
do we add verr/vwarn/vwarnx for completeness, or do we think about deprecating
and eventually dropping the five interfaces which are included?

Navigator shows one app which uses /any/ of the v* set, an anonymized one from
one of the capture programs uses verrx.

err is used by 12, errx by 11, warn by 12, warnx by 11.
[reply] [-] Comment 1