|This version of this document is no longer maintained. For the latest documentation, see http://www.qnx.com/developers/docs.|
Dump the postmortem state of a program (QNX)
dumper [-d path] [-m] [-n] [-p pid] [-s size[G|M|K]] [-v] [-w] [-z level] &
- -d path
- The name of the directory in which to write postmortem dump files. The default is your home directory.
- Don't dump memory.
- 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.
- -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.
- 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
gdb /usr/photon/bin/pterm /var/dumps/pterm.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:
|SIGABRT||Program-called abort function|
|SIGFPE||Floating-point error or division by zero|
|SIGILL||Illegal instruction executed|
|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:
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.
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).