Man Page signal.3f
NAME
signal - change the action for a signal
SYNOPSIS
integer*4 function signal(signum, proc, flag)
integer*4 signum, flag
external proc
For 64-bit environments:
integer*8 function signal(signum, proc, flag)
When compiling for 64-bit environments, with compiler option
-xarch=v9, signal must be declared integer*8 signal as well
as any variables receiving the result from signal.
DESCRIPTION
If a process incurs a signal (see signal(3)), the default
action is usually to clean up and abort. You can choose to
write an alternative signal handling routine. A call to
signal is the way this alternate action is specified to the
system.
Input:
signum is the signal number (see signal(3)).
proc is the name of a user signal handling routine.
If flag is negative, then proc must be the name of the user
signal handling routine.
If flag is zero or positive, then proc is ignored and the
value of flag is passed to the system as the signal action
definition. In particular, this is how previously saved
signal actions can be restored.
Two possible values for flag have specific meanings:
0 means "use the default action." See NOTES below.
1 means "ignore this signal."
Output:
A positive returned value is the previous action defini-
tion.
A value greater than 1 is the address of a routine that was
to have been called on occurrence of the given signal.
A negative returned value is the negation of a system error
code. See perror(3F).
The returned value can be used in subsequent calls to sig-
nal to restore a previous action definition.
FILES
libF77.a
SEE ALSO
kill(1), signal(3c), kill(3F)
NOTES
f77 arranges to trap certain signals when a process is
started. The only way to restore the default f77 action is
to save the returned value from the first call to signal.
If the user signal handler is called, it is passed the sig-
nal number as an integer argument.