Signal handler
A signal handler is a function or mechanism that specifies or performs a response when a signal or notification is delivered.
Modern C, Third Edition
A signal handler is a function invoked in response to a signal raised by an execution environment or program.
- How it is used
- Handles exceptional conditions triggered by synchronous faults or asynchronous external events.
- How deep it goes
- Explains event timing and handler safety, then shows registration and counting interfaces without developing a general recovery procedure.
- Examples
- Uses fault and termination scenarios, signal-registration listings, and a per-signal counter guarded by `ATOMIC_LONG_LOCK_FREE`.
- What you can do after
- Operate/configure it by registering a handler that records a condition and leaves further work to interrupted code.
Modern C
A signal handler is a function invoked by the C signal-handling mechanism when a specified signal is delivered.
- How it is used
- Handles externally triggered exceptional conditions through C's signal mechanism.
- How deep it goes
- Explains synchronous and asynchronous delivery, handler registration, signal-specific responses, and shared-state limits without specifying a general recovery procedure.
- Examples
- Walks through a handler that counts deliveries, exits for SIGTERM or SIGABRT, and records other signals in an interrupt flag.
- What you can do after
- Apply it via signal() to install a handler that records an interrupt condition for later handling.
Django in Action
A signal handler is a callable that receives a signal notification and performs corresponding application logic.
- How it is used
- Automates creation of a related UserProfile when Django saves a newly created User.
- How deep it goes
- Explains observer registration, pre/post timing, receiver arguments, fixture handling, duplicate checks, and ORM creation.
- Examples
- Demonstrates a User post-save receiver that creates a missing UserProfile and verifies the resulting relation.
- What you can do after
- Build it from scratch by registering a post_save receiver that safely creates related profiles.
Rust in Action: Systems programming concepts and techniques
A signal handler is a function or disposition associated with a signal that determines how a process responds when the signal is delivered.
- How it is used
- Uses signal handlers to initiate clean shutdown instead of relying on a signal’s default termination behavior.
- How deep it goes
- Works through registration, handler constraints, and a main-loop flag pattern without developing a general signal-handling reference.
- Examples
- Tests SIGTERM and SIGUSR1 in a looping program and demonstrates ignoring SIGTERM before restoring its default behavior.
- What you can do after
- Apply it via Rust’s libc::signal() to register a minimal handler and let the main loop initiate shutdown.
Read how Rust in Action: Systems programming concepts and techniques explains signal handler →
Related concepts
- signaluses · An operating-system signal is an asynchronous notification delivered to a process to report an event or request handling.
- sig_atomic_tuses · sig_atomic_t is an integer type whose object evaluations and assignments are guaranteed to be indivisible with respect to signal handling.
- post_saveuses · post_save is a Django ORM signal emitted after a model instance has been saved.
- booleanuses · A Boolean is a logical type or value representing truth or falsity, conventionally with two states: true and false.
- signal.huses · signal.h is the standard C header that declares signal-handling functions, types, and constants.
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