Search results
Results from the WOW.Com Content Network
If a signal handler is not installed for a particular signal, the default handler is used. Otherwise the signal is intercepted and the signal handler is invoked. The process can also specify two default behaviors, without creating a handler: ignore the signal (SIG_IGN) and use the default signal handler (SIG_DFL).
This sends the "terminal stop" signal (SIGTSTP) to the process group. By default, SIGTSTP causes processes receiving it to stop, and control is returned to the shell. However, a process can register a signal handler for or ignore SIGTSTP. A process can also be paused with the "stop" signal (SIGSTOP), which cannot be caught or ignored.
Signal handlers can be set with signal() or sigaction(). The behavior of signal() has been changed multiple times across history and its use is discouraged. [3] It is only portable when used to set a signal's disposition to SIG_DFL or SIG_IGN. Signal handlers can be specified for all but two signals (SIGKILL and SIGSTOP cannot be caught ...
The signal number is passed as an integer argument to this function. The sa_mask member specifies additional signals to be blocked during the execution of signal handler. sa_mask must be initialized with sigemptyset(3). The sa_flags member specifies some additional flags. sa_sigaction is an alternate signal handler with different set of parameters.
If the process receiving SIGHUP is a Unix shell, then as part of job control it will often intercept the signal and ensure that all stopped processes are continued before sending the signal to child processes (more precisely, process groups, represented internally by the shell as a "job"), which by default terminates them.
Other times, even a process that has a special handler has gone awry in a way that prevents it from properly handling the signal. All signals except for SIGKILL and SIGSTOP ("stop") can be "intercepted" by the process, meaning that a special function can be called when the program receives those signals.
In asynchronous serial communication, a signal at the end of a character that prepares the receiving device for the reception of a subsequent character. A stop signal is usually limited to one signal element having any duration equal to or greater than a specified minimum value. A signal to a receiving mechanism to wait for the next signal.
In a computer, an interrupt request (or IRQ) is a hardware signal sent to the processor that temporarily stops a running program and allows a special program, an interrupt handler, to run instead. Hardware interrupts are used to handle events such as receiving data from a modem or network card, key presses, or mouse movements.