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Dpkg::IPC(3perl)                 libdpkg-perl                 Dpkg::IPC(3perl)

NAME
       Dpkg::IPC - helper functions for IPC

DESCRIPTION
       Dpkg::IPC offers helper functions to allow you to execute other
       programs in an easy, yet flexible way, while hiding all the gory
       details of IPC (Inter-Process Communication) from you.

FUNCTIONS
       $pid = spawn(%opts)
           Creates  a  child  process and executes another program in it.  The
           arguments are interpreted as a hash of options, specifying  how  to
           handle  the  in  and output of the program to execute.  Returns the
           pid of the child process (unless the wait_child option was given).

           Any error  will  cause  the  function  to  exit  with  one  of  the
           Dpkg::ErrorHandling functions.

           Options:

           exec
               Can  be  either  a  scalar,  i.e. the name of the program to be
               executed, or an array reference, i.e. the name of  the  program
               plus  additional arguments. Note that the program will never be
               executed  via  the  shell,  so  you  can't  specify  additional
               arguments  in  the  scalar  string  and you can't use any shell
               facilities like globbing.

               Mandatory Option.

           from_file, to_file, error_to_file
               Filename as scalar. Standard input/output/error  of  the  child
               process will be redirected to the file specified.

           from_handle, to_handle, error_to_handle
               Filehandle.  Standard  input/output/error  of the child process
               will be dup'ed from the handle.

           from_pipe, to_pipe, error_to_pipe
               Scalar reference or object based on IO::Handle. A pipe will  be
               opened  for  each  of  the  two  options and either the reading
               ("to_pipe"   and   "error_to_pipe")   or   the   writing    end
               ("from_pipe")  will  be  returned  in  the  referenced  scalar.
               Standard input/output/error of the child process will be dup'ed
               to the other ends of the pipes.

           from_string, to_string, error_to_string
               Scalar reference.  Standard  input/output/error  of  the  child
               process  will  be  redirected to the string given as reference.
               Note that it wouldn't be strictly necessary  to  use  a  scalar
               reference  for  "from_string", as the string is not modified in
               any way. This was chosen only  for  reasons  of  symmetry  with
               "to_string"     and    "error_to_string".    "to_string"    and
               "error_to_string" imply the "wait_child" option.

           wait_child
               Scalar. If containing a true value, wait_child() will be called
               before returning. The return value of spawn() will  be  a  true
               value, not the pid.

           nocheck
               Scalar. Option of the wait_child() call.

           timeout
               Scalar. Option of the wait_child() call.

           chdir
               Scalar. The child process will chdir in the indicated directory
               before calling exec.

           env Hash  reference.  The child process will populate %ENV with the
               items of the hash before calling exec.  This  allows  exporting
               environment variables.

           delete_env
               Array  reference. The child process will remove all environment
               variables listed in the array before calling exec.

           sig Hash reference. The child process will populate %SIG  with  the
               items  of  the  hash  before  calling exec. This allows setting
               signal dispositions.

           delete_sig
               Array reference. The  child  process  will  reset  all  signals
               listed  in  the  array  to  their  default  dispositions before
               calling exec.

       wait_child($pid, %opts)
           Takes as first argument  the  pid  of  the  process  to  wait  for.
           Remaining  arguments  are  taken  as  a  hash  of  options. Returns
           nothing. Fails if the child has been ended by a  signal  or  if  it
           exited non-zero.

           Options:

           cmdline
               String  to  identify  the  child  process  in  error  messages.
               Defaults to "child process".

           nocheck
               If true do not check the return status of the child  (and  thus
               do  not fail it has been killed or if it exited with a non-zero
               return code).

           timeout
               Set a maximum time to wait for the process, after that kill the
               process and fail with an error message.

CHANGES
   Version 1.02 (dpkg 1.18.0)
       Change options: wait_child() now kills the process  when  reaching  the
       'timeout'.

   Version 1.01 (dpkg 1.17.11)
       New options: spawn() now accepts 'sig' and 'delete_sig'.

   Version 1.00 (dpkg 1.15.6)
       Mark the module as public.

SEE ALSO
       Dpkg, Dpkg::ErrorHandling.

1.22.6                            2025-09-18                  Dpkg::IPC(3perl)

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