implementing using `memmove` and `malloc` leading to memory corruption in C
I've been working on this all day and I'm sure I'm missing something obvious here, but I'm relatively new to this, so bear with me. I've looked through the documentation and I'm still confused about I'm working with a memory corruption scenario when using `memmove` in conjunction with dynamically allocated memory in C. My program is designed to manipulate a buffer that I allocate using `malloc`, but after calling `memmove`, the buffer seems to get corrupted, resulting in unexpected behaviors. Specifically, I'm trying to shift a portion of the buffer, but after the operation, accessing the elements gives me garbage values or causes a segmentation fault. Here's a simplified version of my code: ```c #include <stdio.h> #include <stdlib.h> #include <string.h> int main() { size_t buffer_size = 10; char *buffer = malloc(buffer_size); if (!buffer) return 1; // Initialize the buffer with some values for (size_t i = 0; i < buffer_size; i++) { buffer[i] = 'A' + i; } printf("Before memmove: %.*s\n", (int)buffer_size, buffer); // Intentionally shifting part of the buffer memmove(buffer + 2, buffer + 5, buffer_size - 5); printf("After memmove: %.*s\n", (int)buffer_size, buffer); free(buffer); return 0; } ``` When I compile and run this code, I expect to see the characters shifted correctly within the buffer, but instead, I get unexpected characters and sometimes a program crash, especially when I access parts of the buffer after calling `memmove`. I’ve made sure that `buffer` has enough allocated memory and that the source and destination regions do not overlap. I checked the return value of `malloc` and verified that it’s not NULL. I also confirmed that I'm not exceeding the bounds of the allocated memory. Can anyone spot what might be going wrong or suggest best practices when using `memmove` with dynamically allocated memory? I'm compiling with gcc version 11.2.0 on Ubuntu 20.04. Any insights would be greatly appreciated! My development environment is Linux. Is there a better approach? I've been using C for about a year now. I'm open to any suggestions. Am I approaching this the right way?