strchg, strconf - Alters and queries stream configuration
strchg -h module1 [,module2,... modulen]
strchg -p [-a | -u module]
strchg -f file
strconf [-t | -m module]
The strchg and strconf commands modify and return information
about the configuration of the Stream associated with
the user's standard input.
The strchg command has three formats, which must be specified
separately. These formats offer the following
options: When used with -p, removes all of the STREAMS
modules above the topmost driver; that is, the command
only affects the uppermost Stream created for a multiplexed
driver, not any of the lower Streams. This option
cannot be used with -u. Specifies a file that contains a
list of STREAMS modules to be pushed on the standard input
Stream for a desired configuration. The names of the modules
must occupy separate lines in the file. The strchg
command pushes any module that is desired but is not present
on the Stream, and pops any module that is not
desired and is present on the Stream. Pushes the STREAMS
module or modules specified by the module argument or
arguments on the standard input Stream. The command
pushes the STREAMS modules on the Stream in the order that
they are specified; that is, module1 is pushed first, module2
is pushed second, and so forth. Pops STREAMS modules
off the standard input Stream. When the -p option is specified
without any other options, the command removes the
topmost module (the module immediately below the Stream
head) from the Stream. The -a and -u options cannot be
used simultaneously with the -p option. When used with
-p, pops all of the modules above the specified module off
the Stream, leaving that module on it. This option cannot
be used with -a.
The strconf command options are the following: Prints the
name of the topmost module on the standard input Stream,
if this module exists. Confirms whether or not the specified
module module is present on the Stream.
The strchg command pushes and pops STREAMS modules on and
off the user's standard input Stream to achieve a desired
configuration. The strconf command queries the configuration
of the Stream, then prints the names of the modules
and the topmost device driver, or the name of the topmost
module, or the name of a specific module.
When the -f option is used, the strchg command first
determines the current configuration of the standard input
Stream, then pushes or pops the modules named in the file
argument to fix it. The module that is named first is
meant to be the one that is located below the Stream head,
while the module named last is meant to be at the bottom
of the Stream, closest to the device driver. This is the
opposite of the order in which the strchg command pushes
and pops modules when it is invoked with the -h option.
To use the strchg command, you must either be the owner of
the Stream or the superuser.
Without options, the strconf command prints the names of
all of the modules, if any, and the name of the topmost
driver. Names are printed one per line, with the driver's
name last. When the autopush mechanism is used in a system,
the strconf command returns the names of the modules
that were automatically pushed on the standard input
Stream at the opening of the associated device. If the
Stream configuration has been changed since the device was
opened, the command prints the altered list of module
names.
If the -t option is used, the strconf command prints only
the topmost module's name, if any exists. When the -m
option is used, the command queries the standard input
Stream for the module specified in the module argument. If
this module is present on the Stream, it prints the message
yes and returns a 0 (zero). If the module is not on
the Stream, strchg prints no and returns a nonzero value.
The -t and -m options cannot be used simultaneously.
To use the strconf command, you must either have read permission
or be the superuser.
For both the strchg and strconf commands, note that if
modules are pushed onto the user's standard input Stream
in the wrong order, that Stream will not function as
expected. For example, in the case of terminal lines
(ttys), the line discipline module must be pushed in the
correct place; otherwise, the terminal might not respond
correctly to commands.
The strchg command returns 0 (zero) on success. When the
command encounters an error, it returns a nonzero status
and prints an error message. The command returns errors
for such conditions as a usage error, bad module name,
failure of an ioctl system call, and failure to open the
file specified by the -f option.
The strconf command returns 0 (zero) on success and a
nonzero status for errors. It prints an error message for
any errors. When the -m and -t options return successfully,
this indicates that the named, or topmost, module
is present. The error conditions that the command returns
a status for include a usage error and a failure of an
ioctl system call.
To print out the names of the modules and driver present
on the user's standard input Stream, enter: strconf To
push the fictional line discipline module linedisp onto
the user's standard input Stream, enter: strchg -h
linedisp
The ldterm module is pushed below the Stream head
in the user's standard input Stream. To set up the
standard input Stream (JIS) characters, and to do
this using a previously created file called
/$HOME/.mytty.conf that lists the modules, enter:
strchg -f $HOME/.mytty.conf
If the list of modules in the /$HOME/.mytty.conf
file is as follows, the fictional lpass module will
be pushed first, followed by the fictional linedisp
module, followed by the fictional upass module.
upass linedisp lpass
Commands: autopush(8)
Interfaces: streamio(7)
strchg(1)
[ Back ] |
