Debugging a Program With dbx

Command Reference

`thread`

In the following commands, a missing tid implies the current thread.

Print everything known about the given thread:

thread -info tid

Hide or unhide the given (or current) thread. It will or will not show up in the generic threads listing:

thread [-hide | -unhide] tid

Unhide all threads:

thread
-unhide all

Keep the given thread from ever running. A suspended thread shows up with an S in the threads list:

thread -suspend tid

Undo the effect of --suspend:

thread -resume tid

Echoes the current modes:

threads -mode

Control whether threads prints all threads or filters them by default:

threads -mode [all | filter]

Table 12-1 Thread and LWP States


Thread and LWP States	Description
suspended	Thread has been explicitly suspended.
runnable	Thread is runnable and is waiting for an LWP as a computational resource.
zombie	When a detached thread exits `(thr_exit))`, it is in a zombie state until it has rendezvoused through the use of `thr_join(). THR_DETACHED` is a flag specified at thread creation time `(thr_create())`. A non-detached thread that exits is in a zombie state until it has been reaped.
asleep on `syncobj`	Thread is blocked on the given synchronization object. Depending on what level of support `libthread` and `libthread_db` provide, `syncobj` might be as simple as a hexadecimal address or something with more information content.
active	The thread is active on an LWP, but `dbx` cannot access the LWP.
unknown	`dbx` cannot determine the state.
`lwpstate`	A bound or active thread state is the state of the LWP associated with it.
running	LWP was running but was stopped in synchrony with some other LWP.
syscall `num`	LWP stopped on an entry into the given system call #.
syscall return `num`	LWP stopped on an exit from the given system call #.
job control	LWP stopped due to job control.
LWP suspended	LWP is blocked in the kernel.
single stepped	LWP has just completed a single step.
breakpoint	LWP has just hit a breakpoint.
fault `num`	LWP has incurred the given fault #.
signal `name`	LWP has incurred the given signal.
process sync	The process to which this LWP belongs has just started executing.
LWP death	LWP is in the process of exiting.