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📛 NAME

Dpkg::IPC — helper functions for IPC

🚀 Quick Reference

Use Case	Command	Description
Execute a program	spawn(%opts)	Creates a child process and executes a program.
Wait for a process	wait_child($pid, %opts)	Waits for a child process to finish.
Redirect stdin/stdout/stderr	from_*, to_*, error_to_*	Redirect I/O to files, handles, pipes, or strings.
Set environment variables	env	Populate %ENV in the child process.
Delete environment variables	delete_env	Remove environment variables in the child process.
Set signal handlers	sig	Populate %SIG in the child process.
Delete signal handlers	delete_sig	Reset signals to default dispositions.
Change directory	chdir	Child process changes directory before exec.
Wait with timeout	timeout	Kill the child process if it exceeds the time limit.

📖 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

📦 spawn(%opts)

$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 — Mandatory. Can be either a scalar (program name) or an array reference (program name + arguments). The program will never be executed via the shell, so you can't specify additional arguments in the scalar string or use shell facilities like globbing.
• 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 IO::Handle object. A pipe will be opened. The reading end (to_pipe and error_to_pipe) or 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 redirected to the string. Note that it wouldn't be strictly necessary to use a scalar reference for from_string, as the string is not modified. This was chosen for symmetry with to_string and error_to_string. to_string and error_to_string imply the wait_child option.
• wait_child — Scalar. If true, 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 to 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)

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 if 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

1.21.1 2025-09-09 Dpkg::IPC(3perl)

📛 NAME 🚀 Quick Reference 📖 DESCRIPTION ⚙️ FUNCTIONS 📜 CHANGES 🔗 SEE ALSO