How do I use core dumps for post-mortem debugging in C++?

Core dumps are valuable tools for post-mortem debugging in C++ applications. When a program crashes, the operating system can generate a core dump, which is a snapshot of the program's memory at the time of the crash. This information can help you analyze the cause of the failure and debug your application effectively.

Generating a Core Dump

To enable core dumps on your system, you may need to adjust your shell settings. For instance, in Unix-like systems, you can use the following command to set the core dump size to unlimited:

Using GDB to Analyze Core Dumps

The GNU Debugger (GDB) is a powerful tool for analyzing core dumps. Here is a basic example of how to use GDB to debug a core dump:

Once GDB is running, you can use various commands to inspect the state of the program during the crash:

• bt: Backtrace to see the function call stack.
• print : Print the value of specific variables.
• list: Show the source code around the point of the crash.

Example: Debugging a Crash

Suppose your C++ application crashed due to an access violation error. You would follow these steps:

1. Enable core dumps using ulimit -c unlimited.
2. Run your application. When it crashes, a core dump file is generated.
3. Use GDB to analyze the core dump: gdb /path/to/your/program /path/to/core/dump.
4. Inspect the backtrace to find the source of the error with bt.