STRCHG(1)STRCHG(1)NAME
strchg, strconf - change or query stream configuration
SYNOPSIS
strchg -h module1 [, module2...]
strchg -p [-a | -u module]
strchg -f filename
strconf [-m | -t module]
DESCRIPTION
These commands are used to alter or query the configuration of the
stream associated with the user's standard input. The strchg command
pushes modules on and/or pops modules off the stream. The strconf com‐
mand queries the configuration of the stream. Only the super-user or
owner of a STREAMS device can alter the configuration of that stream.
Invoked without any arguments, strconf prints a list of all the modules
in the stream as well as the topmost driver. The list is printed with
one name per line where the first name printed is the topmost module on
the stream (if one exists) and the last item printed is the name of the
driver.
OPTIONS
The following options apply to strchg and, -h, -f, and -p are mutually
exclusive.
-a
Pop all the modules above the topmost driver off the stream. This
option requires the -p option.
-f filename
Specify a filename that contains a list of modules representing the
desired configuration of the stream. Each module name must appear
on a separate line where the first name represents the topmost mod‐
ule and the last name represents the module that should be closest
to the driver. strchg determines the current configuration of the
stream and pop and push the necessary modules in order to end up
with the desired configuration.
-h module1 [,module2...]
Mnemonic for push, pushes modules onto a stream. It takes as argu‐
ments the names of one or more pushable streams modules. These mod‐
ules are pushed in order; that is, module1 is pushed first, module2
is pushed second, etc.
-p
Mnemonic for pop, pops modules off the stream. With the -p option
alone, strchg pops the topmost module from the stream.
-u module
All modules above, but not including module are popped off the
stream. This option requires the -p option.
The following options apply to strconf and, -m and -t are mutually
exclusive.
-m module
Determine if the named module is present on a stream. If
it is, strconf prints the message yes and returns zero.
If not, strconf prints the message no and returns a non-
zero value. The -t and -m options are mutually exclusive.
-t module
Print only the topmost module (if one exists). The -t and
-m options are mutually exclusive.
EXAMPLES
Example 1 Using the strchg Command
The following command pushes the module ldterm on the stream associated
with the user's standard input:
example% strchg -h ldterm
The following command pops the topmost module from the stream associ‐
ated with /dev/term/24. The user must be the owner of this device or
the super user.
example% strchg -p < /dev/term/24
If the file fileconf contains the following:
ttcompat
ldterm
ptem
then the command
example% strchg -f fileconf
configures the user's standard input stream so that the module ptem is
pushed over the driver, followed by ldterm and ttcompat closest to the
stream head.
The strconf command with no arguments lists the modules and topmost
driver on the stream; for a stream that has only the module ldterm
pushed above the zs driver, it would produce the following output:
ldterm
zs
The following command asks if ldterm is on the stream:
example% strconf-m ldterm
and produces the following output while returning an exit status of 0:
yes
SEE ALSOattributes(5), streamio(7I)DIAGNOSTICS
strchg returns zero on success. It prints an error message and returns
non-zero status for various error conditions, including usage error,
bad module name, too many modules to push, failure of an ioctl on the
stream, or failure to open filename from the -f option.
strconf returns zero on success (for the -m or -t option, "success"
means the named or topmost module is present). It returns a non-zero
status if invoked with the -m or -t option and the module is not
present. It prints an error message and returns non-zero status for
various error conditions, including usage error or failure of an ioctl
on the stream.
NOTES
If the user is neither the owner of the stream nor the super-user, the
strchg command fails. If the user does not have read permissions on the
stream and is not the super user, the strconf command fails.
If modules are pushed in the wrong order, one could end up with a
stream that does not function as expected. For ttys, if the line disci‐
pline module is not pushed in the correct place, one could have a ter‐
minal that does not respond to any commands.
Mar 24, 2005 STRCHG(1)
