Memory Leak

runtime

No runtime error, but program consumes increasing amounts of memory

Description

The program allocates memory but never frees it, causing the program to consume more and more memory over time.

Common Causes

• Allocating memory with malloc/calloc but not freeing it
• Losing the pointer to allocated memory
• Exiting a function without freeing allocated memory

Example of Error

Error Code

void processData() {
    int *data = malloc(1000 * sizeof(int));
    // Process data
    // Missing free(data)
}

int main() {
    while (1) {
        processData();  // Memory leak on each call
    }
    return 0;
}

Solution

Always free dynamically allocated memory when it's no longer needed.

Corrected Code

void processData() {
    int *data = malloc(1000 * sizeof(int));
    if (data == NULL) {
        return;  // Handle allocation failure
    }
    
    // Process data
    
    free(data);  // Free memory when done
}

int main() {
    while (1) {
        processData();
    }
    return 0;
}

Additional Tips

• For every malloc/calloc, there should be a corresponding free
• Consider using smart pointers or similar techniques in C++
• Use tools like Valgrind to detect memory leaks
• Follow the RAII principle (Resource Acquisition Is Initialization) when possible