Ubuntu Manpage: Dpkg::IPC - helper functions for IPC

Provided by: libdpkg-perl_1.22.6ubuntu6.1_all

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.

NAME

DESCRIPTION

FUNCTIONS

CHANGES

SEE ALSO