On 04/01/16 20:41, Tomas Krcka wrote: > On 01/04/2016 04:10 PM, Jim Meyering wrote: >> On Mon, Jan 4, 2016 at 7:07 AM, Bernhard Voelker >> <[email protected]> wrote: >>> On 01/04/2016 01:34 PM, Pádraig Brady wrote: >>>> --- a/NEWS >>>> +++ b/NEWS >>>> @@ -47,6 +47,9 @@ GNU coreutils NEWS >>>> -*- outline -*- >>>> is reusable by most shells, with non-printable characters escaped >>>> with the POSIX proposed $'...' syntax. >>>> >>>> + stty now supports the -i, --immediate option, to apply settings >>>> + without waiting for transmission of any pending output. >>>> + >>> >>> s/-i/-I/ >>> >>>> --- a/src/stty.c >>>> +++ b/src/stty.c >>> ... >>>> @@ -522,7 +523,7 @@ usage (int status) >>>> else >>>> { >>>> printf (_("\ >>>> -Usage: %s [-F DEVICE | --file=DEVICE] [SETTING]...\n\ >>>> +Usage: %s [-F DEVICE | --file=DEVICE] [-I] [SETTING]...\n\ >>>> or: %s [-F DEVICE | --file=DEVICE] [-a|--all]\n\ >>>> or: %s [-F DEVICE | --file=DEVICE] [-g|--save]\n\ >>>> "), >>>> @@ -538,6 +539,9 @@ Print or change terminal characteristics.\n\ >>>> -g, --save print all current settings in a stty-readable >>>> form\n\ >>>> -F, --file=DEVICE open and use the specified DEVICE instead of >>>> stdin\n\ >>>> "), stdout); >>>> + fputs (_("\ >>>> + -i, --immediate apply setting without waiting for pending >>>> transmission\n\ >>>> +"), stdout); >>> >>> Likewise. >>> >>> Otherwise +1. >> Patch looks fine. >> You might want to add a URL linking to this discussion in the commit log; >> it provides a fine "why would I want this" use case. > Patch is OK, just change -i to capital -I in help as Berny mentioned. > And I would also append the use case (scenario) when it's good to use it. > I spent a lots of time to find out where was the problem, so it can help > someone.
Upon consideration I dislike the asymmetry with providing an --immediate option but without a converse option that could be used on non GNU systems, or on distros that decide to change the default "draining" operation. In the attached I've used a negatable "drain" special setting, which I think is better due to being directly associated with settings, and being reversible using standard stty syntax. thanks, Pádraig
From cb7d8b90a213c0186a8c8ba66da959e1f5930e78 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A1draig=20Brady?= <[email protected]> Date: Wed, 6 Jan 2016 14:40:03 +0000 Subject: [PATCH] stty: support [-]drain setting to control waiting for pending Tx Instead of commit v8.24-132-g5171bef which only provides control to disable this behavior (with -I), provide the symmetrical "[-]drain" special setting. * src/stty.c (main): Parse the [-]drain setting instead of -I, and treat like a global option. (usage): Adjust accordingly. * tests/misc/stty.sh: Test "drain" with and without options. * NEWS: Mention the new feature. --- NEWS | 4 ++-- doc/coreutils.texi | 25 +++++++++++++------------ src/stty.c | 30 ++++++++++++++++++------------ tests/misc/stty.sh | 8 ++++++-- 4 files changed, 39 insertions(+), 28 deletions(-) diff --git a/NEWS b/NEWS index 756042b..6e48a53 100644 --- a/NEWS +++ b/NEWS @@ -47,8 +47,8 @@ GNU coreutils NEWS -*- outline -*- is reusable by most shells, with non-printable characters escaped with the POSIX proposed $'...' syntax. - stty now supports the -I, --immediate option, to apply settings - without waiting for transmission of any pending output. + stty now supports the "[-]drain" setting to control whether to wait + for transmission of pending output before application of settings. ** Changes in behavior diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 85477a0..1fd99d0 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -13808,18 +13808,6 @@ Print all current settings in a form that can be used as an argument to another @command{stty} command to restore the current settings. This option may not be used in combination with any line settings. -@item -I -@itemx --immediate -@opindex -I -@opindex --immediate -@cindex nonblocking @command{stty} setting -Apply settings without first waiting for pending output to be transmitted. -In some cases the system may be in a state where serial transmission -is not possible. -For example, if the system has received the @samp{DC3} character -with @code{ixon} (software flow control) enabled, then @command{stty} would -block without this option. - @end table Many settings can be turned off by preceding them with a @samp{-}. @@ -14439,6 +14427,19 @@ Non-POSIX. @opindex columns Tell the kernel that the terminal has @var{n} columns. Non-POSIX. +@item drain +@opindex drain +@cindex nonblocking @command{stty} setting +Apply settings after first waiting for pending output to be transmitted. +This is enabled by default for GNU @command{stty}. +It is useful to disable this option +in cases where the system may be in a state where serial transmission +is not possible. +For example, if the system has received the @samp{DC3} character +with @code{ixon} (software flow control) enabled, then @command{stty} would +block without @code{-drain} being specified. +May be negated. Non-POSIX. + @item size @opindex size @vindex LINES diff --git a/src/stty.c b/src/stty.c index 93f36de..6a365ad 100644 --- a/src/stty.c +++ b/src/stty.c @@ -464,12 +464,14 @@ static int max_col; /* Current position, to know when to wrap. */ static int current_col; +/* Default "drain" mode for tcsetattr. */ +static int tcsetattr_options = TCSADRAIN; + static struct option const longopts[] = { {"all", no_argument, NULL, 'a'}, {"save", no_argument, NULL, 'g'}, {"file", required_argument, NULL, 'F'}, - {"immediate", no_argument, NULL, 'I'}, {GETOPT_HELP_OPTION_DECL}, {GETOPT_VERSION_OPTION_DECL}, {NULL, 0, NULL, 0} @@ -523,7 +525,7 @@ usage (int status) else { printf (_("\ -Usage: %s [-F DEVICE | --file=DEVICE] [-I] [SETTING]...\n\ +Usage: %s [-F DEVICE | --file=DEVICE] [SETTING]...\n\ or: %s [-F DEVICE | --file=DEVICE] [-a|--all]\n\ or: %s [-F DEVICE | --file=DEVICE] [-g|--save]\n\ "), @@ -539,9 +541,6 @@ Print or change terminal characteristics.\n\ -g, --save print all current settings in a stty-readable form\n\ -F, --file=DEVICE open and use the specified DEVICE instead of stdin\n\ "), stdout); - fputs (_("\ - -I, --immediate apply setting without waiting for pending transmission\n\ -"), stdout); fputs (HELP_OPTION_DESCRIPTION, stdout); fputs (VERSION_OPTION_DESCRIPTION, stdout); fputs (_("\ @@ -620,6 +619,9 @@ Special settings:\n\ * columns N same as cols N\n\ "), stdout); #endif + printf (_("\ + * [-]drain wait for transmission before applying settings (%s by default)\ +\n"), tcsetattr_options == TCSADRAIN ? _("on") : _("off")); fputs (_("\ ispeed N set the input speed to N\n\ "), stdout); @@ -1084,7 +1086,6 @@ main (int argc, char **argv) bool noargs = true; char *file_name = NULL; const char *device_name; - int tcsetattr_options = TCSADRAIN; initialize_main (&argc, &argv); set_program_name (argv[0]); @@ -1108,7 +1109,7 @@ main (int argc, char **argv) stty parses options, be sure it still works with combinations of short and long options, --, POSIXLY_CORRECT, etc. */ - while ((optc = getopt_long (argc - argi, argv + argi, "-agF:I", + while ((optc = getopt_long (argc - argi, argv + argi, "-agF:", longopts, NULL)) != -1) { @@ -1130,16 +1131,16 @@ main (int argc, char **argv) file_name = optarg; break; - case 'I': - tcsetattr_options = TCSANOW; - break; - case_GETOPT_HELP_CHAR; case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); default: - noargs = false; + /* Consider "drain" as an option rather than a setting, + to support: alias stty='stty -drain' etc. */ + if (! STREQ (argv[argi + opti], "-drain") + && ! STREQ (argv[argi + opti], "drain")) + noargs = false; /* Skip the argument containing this unrecognized option; the 2nd pass will analyze it. */ @@ -1216,6 +1217,11 @@ main (int argc, char **argv) ++arg; reversed = true; } + if (STREQ (arg, "drain")) + { + tcsetattr_options = reversed ? TCSANOW : TCSADRAIN; + continue; + } for (i = 0; mode_info[i].name != NULL; ++i) { if (STREQ (arg, mode_info[i].name)) diff --git a/tests/misc/stty.sh b/tests/misc/stty.sh index 88d5796..5735b76 100755 --- a/tests/misc/stty.sh +++ b/tests/misc/stty.sh @@ -35,8 +35,12 @@ stty $(cat $saved_state) || fail=1 # This would segfault prior to sh-utils-2.0j. stty erase - || fail=1 -# Ensure --immediate mode is supported -stty -I erase - || fail=1 +# Ensure "immediate" and "wait" mode supported, with and without settings +for mode in '-drain' 'drain'; do + for opt in 'echo' ''; do + stty "$mode" $opt || fail=1 + done +done # These would improperly ignore invalid options through coreutils 5.2.1. returns_ 1 stty -F 2>/dev/null || fail=1 -- 2.5.0
