(gdb.info) Active Targets

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(gdb.info) Targets

(gdb.info) Target Commands

 
 Active targets
 ==============
 
    There are three classes of targets: processes, core files, and
 executable files.  GDB can work concurrently on up to three active
 targets, one in each class.  This allows you to (for example) start a
 process and inspect its activity without abandoning your work on a core
 file.
 
    For example, if you execute `gdb a.out', then the executable file
 `a.out' is the only active target.  If you designate a core file as
 well--presumably from a prior run that crashed and coredumped--then GDB
 has two active targets and uses them in tandem, looking first in the
 corefile target, then in the executable file, to satisfy requests for
 memory addresses.  (Typically, these two classes of target are
 complementary, since core files contain only a program's read-write
 memory--variables and so on--plus machine status, while executable
 files contain only the program text and initialized data.)
 
    When you type `run', your executable file becomes an active process
 target as well.  When a process target is active, all GDB commands
 requesting memory addresses refer to that target; addresses in an
 active core file or executable file target are obscured while the
 process target is active.
 
    Use the `core-file' and `exec-file' commands to select a new core
 file or executable target ( Commands to specify files Files.).
 To specify as a target a process that is already running, use the
 `attach' command ( Debugging an already-running process Attach.).
 

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(gdb.info) Targets

(gdb.info) Target Commands