How can we know process id of process which is sending the signal
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From: Sanchit on 14 Apr 2008 14:29 How can we know process id of process which is sending the signal?? Process A sends signal to process B. then how can we know process id of A in B??
From: Jens Thoms Toerring on 14 Apr 2008 14:56
Sanchit <sanchitgupta.1(a)gmail.com> wrote: > How can we know process id of process which is sending the signal?? > Process A sends signal to process B. then how can we know process id > of A in B?? If it's possible depends on your system. If the implementation supports the XSI Extension option (this sounds more complicated then it is, just read your man page for sigaction(2) and check if the following is documented ;-) then you set the SA_SIGINFO flag in the 'sa_flags' member of the 'sigaction' structure you pass to sigaction() when installing the handler and then the signal handler function will be called with three arguments instead of just one: void func( int signo, siginfo_t * info, void * context ) Now you can test what the structure of type 'siginfo_t' passed to the signal handler this way tells you: if the value of its 'si_code' member is less than or equal to 0 (or compare it to 'SI_USER'), then the signal was generated by a process (i.e. by kill(2) or raise(2) and is not due to e.g. a segmentation fault etc.) and 'si_pid' member tells you the ID of the process that send the signal. Regards, Jens -- \ Jens Thoms Toerring ___ jt(a)toerring.de \__________________________ http://toerring.de |