advanced patterns with `memcpy` and struct padding in C on ARM architecture
I'm experiencing an scenario when using `memcpy` to copy data into a struct on an ARM architecture. The struct I'm dealing with has members that potentially lead to padding, and I suspect that this is causing some unexpected behavior during the copy operation. Here’s the struct definition: ```c typedef struct { char a; int b; char c; } MyStruct; ``` When I try to use `memcpy` to fill this struct from a byte array, I do it like this: ```c MyStruct my_struct; char data[sizeof(MyStruct)] = { 'A', 0x00, 0x00, 0x00, 0x01, 'B' }; memcpy(&my_struct, data, sizeof(MyStruct)); ``` After the copy, I print the values of my_struct like this: ```c printf("a: %c, b: %d, c: %c\n", my_struct.a, my_struct.b, my_struct.c); ``` However, I get the output `a: A, b: 1, c: B` instead of the expected `a: A, b: 1, c: B` (which seems right, but actually, `c` should be uninitialized or set to zero). I’ve confirmed that the data array is correctly initialized. I also verified that the byte ordering is correct for my ARM setup. I suspect the scenario might be related to padding or alignment, but I don't fully understand how this affects the copy operation. On x86, the memcpy might behave differently, but I need it to work consistently across architectures. Is there a way to ensure the correct behavior on ARM, or do I need to handle the struct packing differently? I’ve read about `#pragma pack()` but I’m not sure how to apply it effectively here. Any insights would be greatly appreciated!