Using dbx (Multithreaded Programming Guide)

Multithreaded Programming Guide

Using `dbx`

The dbx utility is a debugger included in the Sun Studio developer tools, available from http://developers.sun.com/sunstudio/. With the Sun Studio dbx command-line debugger, you can debug and execute source programs that are written in C, C++, and Fortran. You can use dbx by starting it in a terminal window and interactively debugging your program with dbx commands. If you prefer a graphical interface, you can use the same dbx functionality in the Debugging windows of the Sun Studio IDE (Integrated Development Environment). For a description of how to start dbx, see the dbx(1) man page. See the manual Sun Studio 12: Debugging a Program With dbx for an overview of dbx. The Debugging features in the Sun Studio IDE are described in the IDE online help.

See Chapter 11, Debugging Multithreaded Applications, in Sun Studio 12: Debugging a Program With dbx for detailed information about debugging multithreaded programs. The dbx debugger provides commands to manipulate event handlers for thread events, which are described in Appendix B, Event Management, in Sun Studio 12: Debugging a Program With dbx.

All the dbx options that are listed in Table 8–1 can support multithreaded applications.

Table 8–1 dbx Options for MT Programs


Option	Action
`cont at line [-sig signo id]`	Continues execution at `line` with signal `signo`. The `id`, if present, specifies which thread or LWP to continue. The default value is `all`.
`lwp [lwpid]`	Displays current LWP. Switches to given LWP [`lwpid`].
`lwps`	Lists all LWPs in the current process.
`next ... tid`	Steps the given thread. When a function call is skipped, all LWPs are implicitly resumed for the duration of that function call. Nonactive threads cannot be stepped.
`next ... lwpid`	Steps the given LWP. Does not implicitly resume all LWPs when skipping a function. The LWP on which the given thread is active. Does not implicitly resume all LWP when skipping a function.
`step... tid`	Steps the given thread. When a function call is skipped, all LWPs are implicitly resumed for the duration of that function call. Nonactive threads cannot be stepped.
`step... lwpid`	Steps the given LWP. Does not implicitly resume all LWPs when skipping a function.
`stepi... lwpid`	Steps machine instructions (stepping into calls) in the given LWP.
`stepi... tid`	Steps machine instructions in the LWP on which the given thread is active.
`thread [ tid ]`	Displays current thread, or switches to thread `tid`. In all the following variations, omitting the l `tid` implies the current thread.
`thread -info [ tid ]`	Prints everything known about the given thread.
`thread -blocks [ tid ]`	Prints all locks held by the given thread blocking other threads.
`thread -suspend [ tid ]`	Puts the given thread into suspended state, which prevents it from running. A suspended thread displays with an “S” in the `threads` listing.
`thread -resume [ tid ]`	Unsuspends the given thread so it resumes running.
`thread -hide [ tid ]`	Hides the given or current thread. The thread does not appear in the generic `threads` listing.
`thread -unhide [ tid ]`	Unhides the given or current thread.
`thread -unhide all`	Unhides all threads.
`threads`	Prints the list of all known threads.
`threads -all`	Prints threads that are not usually printed (zombies).
`threads -mode all\|filter`	Controls whether `threads` prints all threads or filters threads by default. When filtering is on, threads that have been hidden by the `thread -hide` command are not listed.
`threads -mode auto\|manual`	Enables automatic updating of the thread listing.
`threads -mode`	Echoes the current modes. Any of the previous forms can be followed by a thread or LWP ID to get the traceback for the specified entity.