signal
Sends a signal RPC
signal
sends an operating system RPC (known as “signal”) to a specified process, identified via it’s process ID (“pid”).
The following quote from Wikipedia explains what signals are:
Signals are standardized messages sent to a running program to trigger specific behavior, such as quitting or error handling. They are a limited form of inter-process communication (IPC), typically used in Unix, Unix-like, and other POSIX-compliant operating systems.
A signal is an asynchronous notification sent to a process or to a specific thread within the same process to notify it of an event. Common uses of signals are to interrupt, suspend, terminate or kill a process.
Signals will differ from one operating system to another. You can retrieve a JSON map with supported signals by running signal
without any parameters.
Send a signal:
signal pid SIGNAL
List supported signals:
signal -> <stdout>
function signal.SIGUSR1.trap {
bg {
exec <pid:MOD.SIGNAL_TRAP_PID> $MUREX_EXE -c %(
event onSignalReceived example=SIGUSR1 {
out "SIGUSR1 received..."
}
out "waiting for signal..."
sleep 5
)
}
sleep 2 # just in case `exec` hasn't started yet
signal $MOD.SIGNAL_TRAP_PID SIGUSR1
}
test unit function signal.SIGUSR1.trap %{
StdoutMatch: "waiting for signal...\nSIGUSR1 received...\n"
DataType: str
ExitNum: 0
}
» signal
{
"SIGABRT": "aborted",
"SIGALRM": "alarm clock",
"SIGBUS": "bus error",
"SIGCHLD": "child exited",
"SIGCONT": "continued",
"SIGFPE": "floating point exception",
"SIGHUP": "hangup",
"SIGILL": "illegal instruction",
"SIGINT": "interrupt",
"SIGIO": "I/O possible",
"SIGKILL": "killed",
"SIGPIPE": "broken pipe",
"SIGPROF": "profiling timer expired",
"SIGPWR": "power failure",
"SIGQUIT": "quit",
"SIGSEGV": "segmentation fault",
"SIGSTKFLT": "stack fault",
"SIGSTOP": "stopped (signal)",
"SIGSYS": "bad system call",
"SIGTRAP": "trace/breakpoint trap",
"SIGTSTP": "stopped",
"SIGTTIN": "stopped (tty input)",
"SIGTTOU": "stopped (tty output)",
"SIGURG": "urgent I/O condition",
"SIGUSR1": "user defined signal 1",
"SIGUSR2": "user defined signal 2",
"SIGVTALRM": "virtual timer expired",
"SIGWINCH": "window changed",
"SIGXCPU": "CPU time limit exceeded",
"SIGXFSZ": "file size limit exceeded"
}
SIGINT
“Signal interrupt” – equivalent to pressing ctrl
+c
SIGQUIT
“Signal quit” – requests the process quits and performs a core dumpSIGTERM
“Signal terminate” – request for a processes termination. Similar to SIGINT
SIGUSR1
“Signal user 1” – user definedSIGUSR2
“Signal user 2” – user definedThe interrupts listed above are a subset of what is supported on each operating system. Please consult your operating systems docs for details on each signal and what their function is.
While Windows doesn’t officially support signals, the following POSIX signals are emulated:
var interrupts = map[string]syscall.Signal{
"SIGHUP": syscall.SIGHUP,
"SIGINT": syscall.SIGINT,
"SIGQUIT": syscall.SIGQUIT,
"SIGILL": syscall.SIGILL,
"SIGTRAP": syscall.SIGTRAP,
"SIGABRT": syscall.SIGABRT,
"SIGBUS": syscall.SIGBUS,
"SIGFPE": syscall.SIGFPE,
"SIGKILL": syscall.SIGKILL,
"SIGSEGV": syscall.SIGSEGV,
"SIGPIPE": syscall.SIGPIPE,
"SIGALRM": syscall.SIGALRM,
"SIGTERM": syscall.SIGTERM,
}
Plan 9 is not supported.
Signals can be caught (often referred to as “trapped”) in Murex with an event: signalTrap
. Read below for details.
bg
: Run processes in the backgroundevent
: Event driven programming for shell scriptsout
: Print a string to the stdout with a trailing new line characterThis document was generated from builtins/events/onSignalReceived/signal_doc.yaml.
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Last built on Thu Aug 15 14:38:34 UTC 2024 against commit 50ed9d650ed9d6df391240d3c2c02e623636e508dfcdad1.
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