Dynamic memory in C++ is managed in the heap, which new and delete use. Misuse of new and delete can lead to memory management problems.
The tool valgrind is a platform for dynamic analysis tools that detect multiple issues in a running program. The specific tool in valgrind for detecting memory management problems is memcheck.
The following describes using valgrind on a single-file program Memory.cpp. You can use valgrind with GitHub Codespaces, install it in Ubuntu in Linux or WSL (sudo apt install valgrind), or install Docker in macOS. Note: valgrind in macOS does not work. You can also view a screencast of the following steps.
Before you run valgrind, you need a Debug compile of the program:
The -g command for the compiler is for debug. It adds source-code line number information into the executable program. The debug option on the compiler allows Valgrind to refer to specific line numbers in your code.
Valgrind has many tools with complex options. To run valgrind for detecting memory issues:
Valgrind produces an overwhelming amount of output. The important information is at the end. The interesting parts of the output are the HEAP SUMMARY:, LEAK SUMMARY, and ERROR SUMMARY. An unsuccessful run with memory leaks of Valgrind ends with something like this:
A successful run with no memory leaks of Valgrind ends with something like this: