How to use LLDB to debug C++ programs?

LLDB is used to debug C++ programs, you can use it to: 1. Connect to the program; 2. Set breakpoints; 3. Run the program; 4. Examine variables; 5. Step through execution; 6. View the call stack.

Use LLDB to debug C++ programs

LLDB is a powerful command line debugger that can be used to debug C++ programs. It is included with Xcode and is also available as a standalone tool.

Connecting to LLDB

First, start LLDB and connect to the program you want to debug. You can use the following command:

lldb my_program

Set a breakpoint

Breakpoints allow you to pause the debugger while your program is executing. To set a breakpoint in an object file, use the breakpoint set command. For example:

breakpoint set --line 50

This will set a breakpoint at line 50 in the source file.

Run the program

To run the program, use the run command. For example:

run

Checking variables

While the program is running, you can use the expression command to check variables. For example:

expression counter

This will print the value of variable counter.

Step execution

Step execution allows you to execute a program line by line. To step through a command, use the step command. For example:

step

Continue execution

To continue execution of the program, use the continue command. For example:

continue

Practical case

Suppose you are debugging a crashing application. You can use LLDB to find the cause of the crash.

First, use the run command to run the program. When a program crashes, LLDB will automatically pause and display the crash log.

Next, use the bt command to view the call stack. This will show the function call chain at the time the program crashed.

You can then use the expression command to inspect local variables and step through the code until you find the cause of the crash.

Other Useful LLDB Commands

• frame select: Select the stack frame to inspect.
• disassemble: Disassemble the current function.
• help: Displays a list of all available LLDB commands.

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