Filter
Top Products
13 Specifying a Debugging Target
A target is the execution environment occupied by your program.
Often, GDB runs in the same host environment as your program; in that case, the
debugging target is specified as a side effect when you use the file or core commands.
For HP-UX specific information, see undefined [HP-UX Targets], page undefined.
When you need more flexibility, for example, running GDB on a physically separate
host, or controlling a standalone system over a serial port or a realtime system over a
TCP/IP connection you can use the target command to specify one of the target types
configured for GDB (see “Commands for managing targets” (page 133)).
13.1 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, for
example, to 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 the contents of the program read-write memory, variables, machine status
etc. While the 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
(see “Commands to specify files” (page 125)). To specify as a target a process that is
already running, use the attach command (see “Debugging a Running Process”
(page 44)).
13.2 Commands for managing targets
target type parameters Connects the GDB host environment to a target
machine or process. A target is typically a protocol
for talking to debugging facilities. You use the
argument type to specify the type or protocol of the
target machine.
Further parameters are interpreted by the target
protocol, but typically include things like device
13.1 Active targets 133