Filter
Top Products
18 Canned Sequences of Commands
In addition to breakpoint commands (see “Breakpoint command lists” (page 61)), GDB
provides the following two ways to store sequence of commands for execution as a
unit:
• user-defined commands
• command files
18.1 User-defined commands
A user-defined command is a sequence of GDB commands to which you assign a new
name as a command. This is done with the define command. User commands may
accept up to 10 arguments separated by whitespace. Arguments are accessed within
the user command via $arg0. . . $arg9. The following example illustrates the use
of canned sequence of commands:
define adder
print $arg0 + $arg1 + $arg2
To execute the command use:
adder 1 2 3
This defines the command adder, which prints the sum of its three arguments. Note
the arguments are text substitutions, so they may reference variables, use complex
expressions, or even perform further functions calls.
The following constructs can be used to create canned sequence of commands:
define commandname Define a command named commandname. If there is
already a command by that name, you are asked to
confirm that you want to redefine it. The definition
of the command is made up of other GDB command
lines, which are given following the define
command. The end of these commands is marked by
a line containing end.
if Takes a single argument, which is an expression to
evaluate. It is followed by a series of commands that
are executed only if the expression is true (nonzero).
The if clause can be followed by an optional else
clause. You can add a list of commands to the else
clause which get executed only if the expression is
false.
while
The syntax is similar to if: the command takes a
single argument, which is an expression to evaluate,
and must be followed by the commands to execute,
one per line, terminated by an end. The commands
18.1 User-defined commands 287