Summary of signals
This table describes what each signal means and the default action that QNX OS performs to handle it. Here, default action means what happens if no handler for this specific signal is defined by the application writer.
Signal | Description | Default action |
---|---|---|
SIGABRT | Abnormal termination, issued by functions such as abort() | Kill the process and write a dump file |
SIGALRM | Alarm clock, issued by functions such as alarm() | Kill the process |
SIGBUS | Bus error, or a memory parity error (a QNX OS-specific interpretation). If a second fault occurs while your process is in a signal handler for this fault, the process is terminated. | Kill the process and write a dump file |
SIGCHLD or SIGCLD | A child process terminated | Ignore the signal, but still let the process's children become zombies |
SIGCONT | Continue the process. You can't block this signal. | Make the process continue if it's STOPPED; otherwise ignore the signal |
SIGDEADLK | A mutex deadlock occurred. QNX doesn't generate this signal, it's user-generated (i.e., generated by a user call to a function such as kill, raise, pthread_kill, etc.). SIGDEADLK and SIGEMT refer to the same signal. Some utilities (e.g., gdb, ksh, slay, and kill) know about SIGEMT, but not SIGDEADLK. |
Kill the process and write a dump file |
SIGDOOM | Terminate the process due to insufficient resources (e.g., it's out of memory). This is similar to SIGKILL but you can ignore it. | Kill the process |
SIGEMT | EMT instruction (emulation trap) SIGDEADLK and SIGEMT refer to the same signal. Some utilities (e.g., gdb, ksh, slay, and kill) know about SIGEMT but not SIGDEADLK. |
Kill the process and write a dump file |
SIGFPE | Floating point exception | Kill the process and write a dump file. This signal is delivered for a given floating-point exception only if it is unmasked. By default, all floating-point exceptions are masked. To unmask them, you must call feenableexcept(). |
SIGHUP | Hangup; the session leader died, or the controlling terminal closed | Kill the process |
SIGILLa | Illegal hardware instruction. If a second fault occurs while your thread is in a signal handler for this fault, the process is terminated. | Kill the process and write a dump file |
SIGINT | Interrupt; typically generated when you press CtrlC or CtrlBreak (you can change this with stty) | Kill the process |
SIGIO | Asynchronous I/O | Ignore the signal |
SIGIOT | I/O trap; a synonym for SIGABRT | Kill the process |
SIGKILL | Kill. You can't block, ignore, or catch this signal. | Kill the processb |
SIGPIPE | Write on pipe with no reader | Kill the process |
SIGPOLL | System V name for SIGIO | Ignore the signal |
SIGPROF | Profiling timer expired. POSIX has marked this signal as obsolescent; QNX OS doesn't support profiling timers or send this signal. | Kill the process |
SIGPWR | Power failure | Ignore the signal |
SIGQUIT | Quit; typically generated when you press Ctrl\ (you can change this with stty) | Kill the process and write a dump file |
SIGSEGV | Segmentation violation; an invalid memory reference was detected. If a second fault occurs while your process is in a signal handler for this fault, the process will be terminated. | Kill the process and write a dump file |
SIGSTOP | Stop the process. You can't block, ignore, or catch this signal. | Stop the processb |
SIGSYS | Bad argument to system call | Kill the process and write a dump file |
SIGTERM | Termination signal | Kill the process |
SIGTRAP | Trace trap | Kill the process and write a dump file |
SIGTSTP | Stop signal from tty; typically generated when you press CtrlZ (you can change this with stty) | Stop the process |
SIGTTIN | Background read attempted from control terminal | Stop the process |
SIGTTOU | Background write attempted to control terminal | Stop the process |
SIGURG | Urgent condition on I/O channel | Ignore the signal |
SIGUSR1 | User-defined signal 1 | Kill the process |
SIGUSR2 | User-defined signal 2 | Kill the process |
SIGVTALRM | Virtual timer expired. POSIX has marked this signal as obsolescent; QNX OS doesn't support virtual timers or send this signal. | Kill the process |
SIGWINCH | The size of the terminal window changed | Ignore the signal |
SIGXCPU | Soft CPU time limit exceeded (see the RLIMIT_CPU resource for setrlimit()) | Kill the process and write a dump file |
SIGXFSZ | File size exceeded (see the RLIMIT_FSIZE resource for prlimit()) This happens if the hard limit on disk quotas has been exceeded on a Power-Safe (QNX6) filesystem (see Managing disk quotas) in the QNX OS User's Guide). | Kill the process and write a dump file |
ThreadCtl( _NTO_TCTL_IO, 0 );