Interprocess Communication Signals

Technote (FAQ)
Problem
What is a signal and why does this matter for WebSphere Application Server?
Solution
Signals are used for interprocess communication. For problem determination, it is often helpful to send signals to the WebSphere processes.

Signals
  • HUP 1 hangup
  • INT 2 interrupt (rubout)
  • QUIT 3 quit (ASCII FS)
  • ILL 4 illegal instruction (not reset when caught)
  • TRAP 5 trace trap (not reset when caught)
  • IOT 6 IOT instruction
  • ABRT 6 used by abort, replace SIGIOT in the future
  • EMT 7 EMT instruction
  • FPE 8 floating point exception
  • KILL 9 kill (cannot be caught or ignored)
  • BUS 10 bus error
  • SEGV 11 segmentation violation
  • SYS 12 bad argument to system call
  • PIPE 13 write on a pipe with no one to read it
  • ALRM 14 alarm clock
  • TERM 15 software termination signal from kill
  • USR1 16 user defined signal 1
  • USR2 17 user defined signal 2
  • CLD 18 child status change
  • CHLD 18 child status change alias (POSIX)
  • PWR 19 power-fail restart
  • WINCH 20 window size change
  • URG 21 urgent socket condition
  • POLL 22 pollable event occured
  • IO SIGPOLL socket I/O possible (SIGPOLL alias)
  • STOP 23 stop (cannot be caught or ignored)
  • TSTP 24 user stop requested from tty
  • CONT 25 stopped process has been continued
  • TTIN 26 background tty read attempted
  • TTOU 27 background tty write attempted
  • VTALRM 28 virtual timer expired
  • PROF 29 profiling timer expired
  • XCPU 30 exceeded cpu limit
  • XFSZ 31 exceeded file size limit
  • WAITING 32 process's lwps are blocked
  • LWP 33 special signal used by thread library
  • FREEZE 34 special signal used by CPR
  • THAW 35 special signal used by CPR

See whitepaper on signals:
http://www.ibm.com/support/docview.wss?rs=180&context=SSEQTP&uid=swg27003858

Each operating system has a unique list of signals.











Document Information

Product categories: Software, Application Servers, Distributed Application & Web Servers, WebSphere Application Server
Operating system(s): AIX, Linux, Solaris
Software version: 3.5, 4.0, 5.0, 5.1, 6.0
Software edition: Edition Independent
Reference #: 1169590
IBM Group: Software Group
Modified date: 2004-09-06