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  man pages->Tru64 Unix man pages -> strchg (1)              



NAME    [Toc]    [Back]

       strchg, strconf - Alters and queries stream configuration

SYNOPSIS    [Toc]    [Back]

       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.

OPTIONS    [Toc]    [Back]

       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.

DESCRIPTION    [Toc]    [Back]

       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

       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.

EXIT STATUS    [Toc]    [Back]

       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.

EXAMPLES    [Toc]    [Back]

       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

              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

SEE ALSO    [Toc]    [Back]

       Commands:  autopush(8)

       Interfaces:  streamio(7)

[ Back ]
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