HP-UX Programmer's Guide for Java 2

Replaced by the -Xusealtsigs option. Instructs the JVM to use SIGUSR2 instead of
the default SIGUSR1 to control the behavior of the JVM runtime. When your application
requires use of a native code library that uses SIGUSR1, use this option to avoid a
conflict between the two runtimes.
The HotSpot VM for Itanium systems uses the following immediate value ranges on
break instructions for internal use. Native program code must not execute a break
instruction with the immediate operand in any of these ranges,or HotSpot will intercept
and interpret the SIGimm signal received by the operating system when the break
instruction is encountered.
0x48000 - 0x49000
0x4c000 - 0x80000
Signal chaining functionality
Beginning with JDK 1.4 a new feature was added for chaining an application's signal
handlers behind the JVM's signal handlers. With signal chaining functionality,
applications can now use signals that the JVM uses and not interfere with the JVM's
functionality. To obtain this functionality, you need to install a HP-UX patch (described
below).
For signal chaining functionality, the application must load the library libjsig.sl
before libc.2.
libjsig.sl takes care of signal chaining when the application's signal handlers are
installed before or after the VM's handlers get installed. libjsig.sl is not needed when
the application installs the handlers before the JVM installs its handlers.
There are two cases to consider:
1. Native application creates a JVM
The application can either link in libjsig.sl and ensure that libjsig.sl
gets loaded before libc.2 by linking them in the right order or use the
LD_PRELOAD_ONCE functionality provided by the linker to load libjsig.sl
first.
2. Normal Java application invoked from the command line
LD_PRELOAD_ONCE must be used in this case. Linking the native libraries with
libjsig will not work because the JVM will load libc.2 before the application's
shared libraries get loaded.
For example, to use the LD_PRELOAD_ONCE environment variable as follows:
LD_PRELOAD_ONCE=/some/lib/I/care/about.sl; program ...
To obtain the LD_PRELOAD_ONCE functionality, you need to install the patch (or
the patch that supersedes it) shown below.
For HP-UX 11.00 systems, install patch PHSS_26559. For HP-UX 11.11 systems,
install patch PHSS_26560.
42 Using Signals