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


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 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.


AUTHORS

       Written by Raphael Hertzog <hertzog@debian.org> and Frank Lichtenheld
       <djpig@debian.org>.


SEE ALSO

       Dpkg, Dpkg::ErrorHandling

1.18.4                            2015-11-26                      Dpkg::IPC(3)

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