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question about UNIX Signal

question about UNIX Signal# Unix - 噫吁兮，危乎高哉

j*e2002-08-22 07:08

1 楼

I install a signal handler for a process.
The handler will catch all the signals except 9 and 23, and do nothing but
"print", and so on.
I found out that that: When the process receive the same signal for a second
time, the handler will not function anymore. And default action for that
signal will take effect.
I can't find any book mention such problem.
Is this a bug in my program, or it is the way that signal works?

m*e2002-08-22 07:08

2 楼

This is how signal works on some Unix platform. You need to catch the signal
again in your signal handler.

【在 j*******e 的大作中提到】

: I install a signal handler for a process.
: The handler will catch all the signals except 9 and 23, and do nothing but
: "print", and so on.
: I found out that that: When the process receive the same signal for a second
: time, the handler will not function anymore. And default action for that
: signal will take effect.
: I can't find any book mention such problem.
: Is this a bug in my program, or it is the way that signal works?

o*z2002-08-22 07:08

3 楼

If you set SA_RESETHAND and the signal is caught,
the disposition of the signal is automatically reset to SIG_DFL

【在 j*******e 的大作中提到】

: I install a signal handler for a process.
: The handler will catch all the signals except 9 and 23, and do nothing but
: "print", and so on.
: I found out that that: When the process receive the same signal for a second
: time, the handler will not function anymore. And default action for that
: signal will take effect.
: I can't find any book mention such problem.
: Is this a bug in my program, or it is the way that signal works?

p*f2002-08-22 07:08

4 楼

If you are using signal(2), change to sigaction(2).

【在 j*******e 的大作中提到】

: I install a signal handler for a process.
: The handler will catch all the signals except 9 and 23, and do nothing but
: "print", and so on.
: I found out that that: When the process receive the same signal for a second
: time, the handler will not function anymore. And default action for that
: signal will take effect.
: I can't find any book mention such problem.
: Is this a bug in my program, or it is the way that signal works?

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