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]

       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 command 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.

       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 module 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 arguments 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.

       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 associated 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 attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

       attributes(5), streamio(7I)

       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 vari-
       ous error conditions, including usage error or failure of an ioctl on the stream.

       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 terminal that does not respond to any commands.

								    24 Mar 2005 							 strchg(1)