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Amend the previous change: we can have (almost) the best of both 

worlds, as when the first arg (which should be the format) contains
no % conversions, and there are more args, the results are unspecified
(according to POSIX).

We can use this so the previous usage
	printf -- format arg...
(which is stupid, and pointless, but used to work) continues to
simply ignore the -- (unspecified results mean we can do whatever
feels good...)

This brings back the #if 0'd block from the previous modification
(so there is no longer anything that needs cleaning up later) but runs
the getopt() loop it contained only when there are at least 2 args
(so any 1 arg printf always uses that arg as the format string,
whatever it contains, including just "--") and also only when the
first (format) arg contains no '%' characters (which guarantees no %
conversions without needing to actually parse the arg).  This is the
(or a) "unspecified results" case from POSIX, so we are free to do
anything we like - including assuming that we might have options
(we don't) and pretending to process them.
This commit is contained in:
kre 2019-07-22 17:34:31 +00:00
parent d3d2abdc28
commit 8ad10c91e9
1 changed files with 29 additions and 17 deletions
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46
usr.bin/printf/printf.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: printf.c,v 1.49 2019/07/21 15:25:39 kre Exp $ */
/* $NetBSD: printf.c,v 1.50 2019/07/22 17:34:31 kre Exp $ */
/*
* Copyright (c) 1989, 1993
@ -41,7 +41,7 @@ __COPYRIGHT("@(#) Copyright (c) 1989, 1993\
#if 0
static char sccsid[] = "@(#)printf.c 8.2 (Berkeley) 3/22/95";
#else
__RCSID("$NetBSD: printf.c,v 1.49 2019/07/21 15:25:39 kre Exp $");
__RCSID("$NetBSD: printf.c,v 1.50 2019/07/22 17:34:31 kre Exp $");
#endif
#endif /* not lint */
@ -138,27 +138,39 @@ main(int argc, char *argv[])
rval = 0; /* clear for builtin versions (avoid holdover) */
#if 0
int o;
/*
* printf does not comply with Posix XBD 12.2 - there are no opts,
* not even the -- end of options marker. Do not run getoot().
*/
while ((o = getopt(argc, argv, "")) != -1) {
switch (o) {
case '?':
default:
usage();
return 1;
if (argc > 2 && strchr(argv[1], '%') == NULL) {
int o;
/*
* except that if there are multiple args and
* the first (the nominal format) contains no '%'
* conversions (which we will approximate as no '%'
* characters at all, conversions or not) then the
* results are unspecified, and we can do what we
* like. So in that case, for some backward compat
* to scripts which (stupidly) do:
* printf -- format args
* process this case the old way.
*/
while ((o = getopt(argc, argv, "")) != -1) {
switch (o) {
case '?':
default:
usage();
return 1;
}
}
argc -= optind;
argv += optind;
} else {
argc -= 1; /* drop argv[0] (the program name) */
argv += 1;
}
argc -= optind;
argv += optind;
#else
argc -= 1;
argv += 1;
#endif
if (argc < 1) {
usage();