The signal number (consider using constants
like SIGUSR1 from the tools package).
testname
Name for this test. Default is to build from
signo argument.
no.signal
Logical, to invert the sense of the test.
Default, FALSE, means to test that the signal was delivered.
TRUE means to test that the signal was not delivered.
Value
The value of the evaluated expression, invisibly,
so you can do more testing if desired.
Details
Check if an expression results in a signal being delivered.
The signal will be caught: you can safely deliver a signal
such as SIGUSR1 that would normally cause the process to die.