SIGQUIT

SIGQUIT is a signal defined by POSIX for Unix-like systems that requests a process to terminate and produce a core dump. It is typically generated by the quit character on a terminal, usually the key combination Ctrl-\, which sends the signal to the foreground process group. The exact delivery and behavior can vary slightly across different systems.

The default action of SIGQUIT is to terminate the process and generate a core dump. A process can install a handler for SIGQUIT to perform custom cleanup or to ignore the signal. If a handler is installed that does not terminate the process, a core dump may not be produced, depending on the handler’s behavior.

Whether a core dump is actually created depends on system configuration and resource limits. Core dumps are typically controlled by system settings such as the core file size limit. If core dumps are disabled or restricted, no core file will be produced even when SIGQUIT is delivered. Some systems may route core dump data to centralized logging or crash reporting tools instead of creating a local core file.

SIGQUIT is distinct from other terminal-generated signals, notably SIGINT (interrupt from Ctrl-C). The availability and handling of SIGQUIT, including its signal number and behavior, can vary across Unix-like operating systems, though it remains a standard part of POSIX signal handling. Programs often use sigaction for portable, explicit control over SIGQUIT behavior.