NEW INTERVIEW QUESTIONS.COM OPERATING SYSTEMS INTERVIEW QUESTIONS UNIX COMMANDS INTERVIEW QUESTIONS DETAILS

Add to My Questions | Forward | Print

Question

Explain kill() and its possible return values.

Answer

There are four possible results from this call: ?kill()? returns 0. This implies that a process exists with the given PID, and the system would allow you to send signals to it. It is system-dependent whether the process could be a zombie. ?kill()? returns -1, ?errno == ESRCH? either no process exists with the given PID, or security enhancements are causing the system to deny its existence. (On some systems, the process could be a zombie.) ?kill()? returns -1, ?errno == EPERM? the system would not allow you to kill the specified process. This means that either the process exists (again, it could be a zombie) or draconian security enhancements are present (e.g. your process is not allowed to send signals to *anybody*). ?kill()? returns -1, with some other value of ?errno? you are in trouble! The most-used technique is to assume that success or failure with ?EPERM? implies that the process exists, and any other error implies that it doesn't. An alternative exists, if you are writing specifically for a system (or all those systems) that provide a ?/proc? filesystem: checking for the existence of ?/proc/PID? may work. © NewInterviewQuestions.com

Answer:*
Name:*
Email Address:*
Verification Code	Not readable? Load New Code
Enter the above shown code:*

Category	Unix Commands Interview Questions
Rating	(4.4) By 5 users
Added	10/25/2004
Views	155313
Rate it!	* * * * * * * * * * * * * * *
Free Offers:	300 Free Magazines for you. No credit card required. No Shipping Charges. Absolutely Free for 1 Year.

Please Note: We keep on updating better answers to this site. Subscribe to our newsletter to get notified when better answer is posted.

Notify me when better answer is posted!
Email: