Debugging with GDB Manual The GNU Source-Level Debugger (769148-001, March 2014)

• Support for debugging large core files (> 2GB)
HP WDB supports debugging of core files with sizes more than 2 GB.
• Support co-variant type
HP WDB can step into a co-variant function. The compiler-generated function called thunks,
which is used internally by the compiler to support co-variant return type, is not shown when
you do a backtrace or switch from one frame to another frame. Similarly, using a finish or
return command at a co-variant callee function directly returns the control back to the caller
of thunks.
• New attach command line options and handling (-pid or -p)
HP WDB accepts -pid or -p followed by a process ID to attach a running process to the
debugger.
NOTE: HP WDB cannot be attached to a process that is traced by tools which use ttrace, such
as Caliper, adb, and tusc. The debugger displays the following error message on attempting to
attach to such a process:
Attaching to process <pid> failed.
Hint: Check if this process is already being traced by another gdb or
other trace tools like caliper and tusc.
Hint: Check whether program is on an NFS-mounted file-system.
If so, you will need to mount the file system with the "nointr" option
with mount(1) or make a local copy of the program to resolve this problem.
HP-UX targets
On HP-UX systems, GDB has been configured to support debugging of processes running on the
PA-RISC and Itanium architectures. This means that the only possible targets are:
• An executable that has been compiled and linked to run on HP-UX. This includes binaries that
have been marked as SHMEM_MAGIC.
• A live HP-UX process, either started by HP WDB (with the run command) or started outside
of HP WDB and attached to (with the attach command).
• A core file generated by an HP-UX process that previously aborted execution.
GDB on HP-UX has not been configured to support remote debugging, or to support programs
running on other platforms.
HP WDB can only debug C++ programs compiled with HP aC++, the ANSI-compatible C++
compiler.
Support for Alternate root
HP WDB supports alternate root functionality, which is helpful when you do not want to use the
system-installed HP WDB or its components.
The environment variable WDB_ROOT specifies the alternate root for HP WDB. You must specify a
structure similar to the default /opt/langtools used for HP WDB. You can use the environment
variable GDB_ROOT to specify an alternate root for GDB.
If you specify both WDB_ROOT and GDB_ROOT, the value for GDB_ROOT is ignored.
HP WDB supports these environment variables to override the location of different component of
HP WDB.
$GDB_SERVERGDB_ROOT/opt/langtools/binDefined Variable
n/an/a/opt/langtools/libWDB Location
LIBRTC_SERVER$GDB_ROOT/binWDB_ROOTGDB location
HP-UX targets 101