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-rw-r--r--NEWS3
-rw-r--r--doc/coreutils.texi12
-rw-r--r--src/stty.c15
-rwxr-xr-xtests/misc/stty.sh3
4 files changed, 30 insertions, 3 deletions
diff --git a/NEWS b/NEWS
index 72d69b8b5..756042b3e 100644
--- 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.
+
** Changes in behavior
base64 no longer supports hex or oct --wrap parameters,
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 62955a508..85477a05a 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -13808,6 +13808,18 @@ 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{-}.
diff --git a/src/stty.c b/src/stty.c
index 37fbb25be..93f36de35 100644
--- a/src/stty.c
+++ b/src/stty.c
@@ -469,6 +469,7 @@ 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}
@@ -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);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
fputs (_("\
@@ -1080,6 +1084,7 @@ 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]);
@@ -1103,7 +1108,7 @@ 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:",
+ while ((optc = getopt_long (argc - argi, argv + argi, "-agF:I",
longopts, NULL))
!= -1)
{
@@ -1125,6 +1130,10 @@ 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);
@@ -1361,7 +1370,7 @@ main (int argc, char **argv)
spurious difference in an uninitialized portion of the structure. */
static struct termios new_mode;
- if (tcsetattr (STDIN_FILENO, TCSADRAIN, &mode))
+ if (tcsetattr (STDIN_FILENO, tcsetattr_options, &mode))
error (EXIT_FAILURE, errno, "%s", quotef (device_name));
/* POSIX (according to Zlotnick's book) tcsetattr returns zero if
diff --git a/tests/misc/stty.sh b/tests/misc/stty.sh
index 666ac0b26..88d5796cf 100755
--- a/tests/misc/stty.sh
+++ b/tests/misc/stty.sh
@@ -35,6 +35,9 @@ 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
+
# These would improperly ignore invalid options through coreutils 5.2.1.
returns_ 1 stty -F 2>/dev/null || fail=1
returns_ 1 stty -raw -F no/such/file 2>/dev/null || fail=1