Watches POSIX signals via signalfd and dispatches them through a callback. More...

#include <dfx-fdwatch/SignalFdWatcher.hpp>

Public Types
enum class	SigChldMode { Default = 0x01 , NoChldStop = 0x02 , NoChldWait = 0x04 }
	Additional behavior configuration for SIGCHLD. More...
using	Callback = std::move_only_function<void (signalfd_siginfo const &)>
	Callback invoked for each received signal. The callback receives the signalfd_siginfo payload read from the FD.

Public Member Functions
	DECLARE_FLAGS (SigChldModes, SigChldMode)
	SignalFdWatcher (Poller &poller, std::initializer_list< int > signals, Callback cb, SigChldModes sigChldModes=SigChldMode::Default)
	Constructs a watcher and registers the internal signalfd into the poller.
	DISABLE_COPY_AND_MOVE (SignalFdWatcher)

Detailed Description

Watches POSIX signals via signalfd and dispatches them through a callback.

SignalFdWatcher creates a signalfd that receives the specified signals and registers it to a Poller. When a signal is delivered, the watcher reads the pending signalfd_siginfo and invokes the user callback.

This approach makes signal handling event-loop friendly (no async-signal-safe restrictions in the callback) and integrates naturally with epoll/poll based loops.

The watcher owns the underlying FD through PollerFd and deregistration/cleanup happens as part of its lifetime management.

Note: For signals to be routed to signalfd, they must be blocked in the thread(s) that should not handle them via traditional signal handlers. This class does the signal masking in its constructor.

Member Typedef Documentation

◆ Callback

using dfx::FdWatch::SignalFdWatcher::Callback = std::move_only_function<void (signalfd_siginfo const &)>

Callback invoked for each received signal. The callback receives the signalfd_siginfo payload read from the FD.

Member Enumeration Documentation

◆ SigChldMode

enum class dfx::FdWatch::SignalFdWatcher::SigChldMode

strong

Additional behavior configuration for SIGCHLD.

These options are only meaningful when watching SIGCHLD. They typically correspond to sigaction() flags such as SA_NOCLDSTOP and SA_NOCLDWAIT.

Enumerator
Default	Default SIGCHLD behavior.
NoChldStop	Do not generate SIGCHLD when children stop/continue (SA_NOCLDSTOP).
NoChldWait	Request that child exit does not leave zombies (SA_NOCLDWAIT).

Constructor & Destructor Documentation

◆ SignalFdWatcher()

dfx::FdWatch::SignalFdWatcher::SignalFdWatcher	(	Poller &	poller,
		std::initializer_list< int >	signals,
		Callback	cb,
		SigChldModes	sigChldModes = SigChldMode::Default )

Constructs a watcher and registers the internal signalfd into the poller.

Parameters

poller	Poller used to monitor the signalfd.
signals	List of signals to route to signalfd (e.g. {SIGINT, SIGTERM}).
cb	Callback invoked when a watched signal is received.
sigChldModes	Optional SIGCHLD behavior flags (only relevant if SIGCHLD is in `signals`).

Precondition: cb must be valid.

Note: This class is non-copyable and non-movable

The documentation for this class was generated from the following file:

lib/dfx-fdwatch/SignalFdWatcher.hpp

Public Types