Dump the postmortem state of a program (QNX)


dumper [-bFfmnPStvw] [-D path] [-d path] [-N max_files]
       [-p pid] [-s size[G|M|K]]
       [-U user_name | uid[:gid[,sup_gid]*]]]
       [-z level] &

Runs on:



Attempt to slog a backtrace (libbacktrace.so.1 must be available).
-D path
The same as -d, but without querying authman.
-d path
The directory in which to place dumps, if authman doesn't supply an application sandbox path. The default is the home directory of user that started the process, or /tmp if none.
Run at a fixed priority.
Follow soft links for the creation of the dump files. The use of this option has security implications.
Don't dump memory.
-N max_files
Save sequential dumps, to a maximum of the given number of files. Each dump is saved in a file whose name is in the form:


where num starts at 1 and increases until the filename doesn't already exist.

Save sequential dumps. Each dump is saved in a file whose name is in the form:


where num starts at 1 and increases until the filename doesn't already exist.

Disable the dumping of shared memory mappings.
Dump the physical memory mappings.
-p pid
Save a dump file for this process immediately, and then exit dumper.
-s size[G|M|K]
Set the maximum core size, in bytes.
Dump the stack of the errant thread only, instead of for all threads.
-U user_name
-U uid[:gid[,sup_gid]*]]
Once running, run as the specified user, so that the program doesn't need to run as root:
  • In the first form, the service sets itself to be the named user and uses that user's groups. This form depends on the /etc/passwd and /etc/group files.
  • In the second form, the service sets its user ID, and optionally its group ID and supplementary groups, to the values provided.
Be verbose.
Make core files world-readable.
-z level
Use gzip to compress the core files. The compression level must be in the range from 1 (fastest) through 9 (best compressed).


The dumper utility runs in the background and provides a postmortem dump service for all processes. Whenever a program terminates abnormally, a dump of the current state of the program is written to disk. The dump filename is the same as the program name with a .core extension. For example, if the program name is experiment, the dump is written to experiment.core in your home directory.

  • On a QNX Momentics system, dumper starts with dumper -d /var/dumps. You can use the -d option to force all dumps into a directory other than /var/dumps.
  • Dump files can be large, so make sure the destination filesystem has lots of space.

The -p option lets you get a dump immediately for a particular process. If you specify -p, dumper doesn't run in the background, but exits right away.

You can use a debugger such as gdb to examine a dump file:

gdb program_binary program_core 

A program may terminate in one of two ways: it may exit cleanly under its own control, returning an exit status, or it may be forcibly terminated by the receipt of a signal that it isn't prepared to handle. In the latter case, dumper writes a dump file for the following set of signals:

Signal Description
SIGABRT Program-called abort function
SIGBUS Parity error
SIGEMT EMT instruction
SIGFPE Floating-point error or division by zero
SIGILL Illegal instruction executed
SIGSEGV Segmentation violation
SIGSYS Bad argument to a system call
SIGTRAP Trace trap (not reset when caught)
SIGXCPU Exceeded the CPU limit
SIGXFSZ Exceeded the file size limit

You can force the dump of a running program by setting one of the preceding signals, assuming that the program isn't masking or handling the signal itself.

For example, to force a dump using the kill command and a process ID (pid):

kill -SIGABRT pid

To force a dump using the slay utility and the process name:

slay -s SIGABRT process_name


Start dumper, with dump files to be written to the default directory:

dumper &

Start dumper, with dump files to be placed in the directory /home/dumps:

dumper -d /home/dumps &


A special entry in the /proc filesystem (see procnto*) that receives notification when a process terminates abnormally.

Exit status:

The dumper utility normally doesn't terminate. However, it may terminate if it encounters an error on startup (for instance, if it wasn't run by root) or if it receives a signal.

A signal was received and dumper shut down successfully.
An error was encountered on startup (not run by root or bad command-line options).