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Annotation of cci/usr/src/man/man3/signal.3f, revision 1.1.1.1

1.1       root        1: .TH SIGNAL 3F "18 July 1983"
                      2: .UC 4
                      3: .SH NAME
                      4: signal \- change the action for a signal
                      5: .SH SYNOPSIS
                      6: .B integer function signal(signum, proc, flag)
                      7: .br
                      8: .B integer signum, flag
                      9: .br
                     10: .B external proc
                     11: .SH DESCRIPTION
                     12: When a process incurs a signal (see
                     13: .IR signal (3C))
                     14: the default action
                     15: is usually to clean up and abort.
                     16: The user may choose to write an alternative signal handling routine.
                     17: A call to
                     18: .I signal
                     19: is the way this alternate action is specified to the system.
                     20: .PP
                     21: .I Signum
                     22: is the signal number (see
                     23: .IR signal (3C)).
                     24: If
                     25: .I flag
                     26: is negative, then
                     27: .I proc
                     28: must be the name of the user signal handling routine.
                     29: If
                     30: .I flag
                     31: is zero or positive, then
                     32: .I proc
                     33: is ignored and the value of
                     34: .I flag
                     35: is passed to the system as the signal action definition.
                     36: In particular, this is how previously saved signal actions can be restored.
                     37: Two possible values for
                     38: .I flag
                     39: have specific meanings:
                     40: 0 means "use the default action" (See NOTES below),
                     41: 1 means "ignore this signal".
                     42: .PP
                     43: A positive returned value is the previous action definition.
                     44: A value greater than 1 is the address of a routine that
                     45: was to have been called on occurrence of the given signal.
                     46: The returned value can be used in subsequent calls to
                     47: .I signal
                     48: in order to restore a previous action definition.
                     49: A negative returned value is the negation of a system error code.
                     50: (See
                     51: .IR perror (3F))
                     52: .SH FILES
                     53: .ie \nM /usr/ucb/lib/libU77.a
                     54: .el /usr/lib/libU77.a
                     55: .SH "SEE ALSO"
                     56: signal(3C), kill(3F), kill(1)
                     57: .SH NOTES
                     58: .B f77
                     59: arranges to trap certain signals when a process is started.
                     60: The only way to restore the default
                     61: .B f77
                     62: action is to save the returned
                     63: value from the first call to
                     64: .I signal.
                     65: .PP
                     66: If the user signal handler is called, it will be passed the signal number
                     67: as an integer argument.

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