ah-signal.H File Reference

POSIX signal handling utilities with RAII semantics. More...

#include <csignal>
#include <cstring>
#include <iostream>
#include <stdexcept>
#include <string>
#include <initializer_list>
#include <aleph.H>

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Classes
class	SignalError
	Exception thrown when a signal operation fails. More...
class	SignalSet
	C++ wrapper for sigset_t with a fluent interface. More...
class	SignalBlocker
	RAII wrapper for temporarily blocking signals. More...
class	Signal
	RAII wrapper for POSIX signal handler registration. More...
struct	Signal::NoAbortTag

Functions
int	wait_for_signal (const SignalSet &signals)
	Utility to wait for a signal.
bool	send_signal_to_self (int signo) noexcept
	Sends a signal to the current process.
std::string	signal_name (int signo)
	Returns the name of a signal.
std::string	signal_description (int signo)
	Returns a human-readable description of a signal.

Detailed Description

POSIX signal handling utilities with RAII semantics.

This header provides C++ wrappers for POSIX signal handling:

• Signal: RAII wrapper for signal handler registration. Automatically restores the previous handler when the object is destroyed.
• SignalSet: C++ wrapper for sigset_t with a fluent interface.
• SignalBlocker: RAII utility to temporarily block signals.

Thread Safety

Signal handlers are process-wide (not per-thread). While the classes in this header are safe to use, be aware that:

• Signal handlers affect the entire process
• Signal masks can be set per-thread using pthread_sigmask
• SignalBlocker uses sigprocmask (process-wide) by default

Example Usage

#include <ah-signal.H>
 
volatile sig_atomic_t got_signal = 0;
 
void handler(int signo) {
    got_signal = signo;
}
 
int main() {
    // Install handler - previous handler is saved
    Signal sig(SIGINT, handler);
 
    // ... do work ...
 
    // When 'sig' goes out of scope, previous handler is restored
}

Author

Leandro Rabindranath León

Definition in file ah-signal.H.

Function Documentation

send_signal_to_self()

bool send_signal_to_self ( int  signo )

inlinenoexcept

Sends a signal to the current process.

Convenience wrapper for raise().

Parameters

signo

The signal to send.

Returns

true if successful, false otherwise.

Definition at line 652 of file ah-signal.H.

Referenced by TEST().

signal_description()

std::string signal_description ( int  signo )

inline

Returns a human-readable description of a signal.

Uses strsignal() if available, otherwise returns the signal name.

Parameters

signo

The signal number.

Returns

A descriptive string for the signal.

Definition at line 730 of file ah-signal.H.

References signal_name().

signal_name()

std::string signal_name ( int  signo )

inline

Returns the name of a signal.

Returns the standard POSIX signal name (e.g., "SIGINT", "SIGTERM").

Parameters

signo

The signal number.

Returns

A string with the signal name or "Signal N" if unknown.

Definition at line 665 of file ah-signal.H.

Referenced by signal_description(), and TEST().

wait_for_signal()

int wait_for_signal ( const SignalSet &  signals )

inline

Utility to wait for a signal.

Blocks until one of the specified signals is delivered.

Parameters

signals

The set of signals to wait for.

Returns

The signal number that was delivered.

Exceptions

SignalError

if sigwait fails.

Example

SignalSet wait_for({SIGINT, SIGTERM});
SignalBlocker blocker(wait_for);  // Block first, then wait
 
int sig = wait_for_signal(wait_for);
std::cout << "Received signal " << sig << std::endl;

Definition at line 635 of file ah-signal.H.

References SignalSet::get().