How much memory does a call to 'malloc' allocate?

In C programming, the malloc function is used to allocate memory on the heap. When calling malloc(1) to allocate just one byte, the actual memory allocated includes some fixed overhead per allocation, typically around 8 bytes of metadata. This overhead is used by the system to manage memory allocations and cannot be utilized by the program. Additionally, due to memory alignment and rounding, a request for 1 byte may result in a chunk of usable memory ranging from 16 to 24 bytes. It is common for memory allocations to be aligned to certain boundaries, like 16 bytes. Systems like Linux and macOS provide functions like malloc_usable_size and malloc_size to determine the actual memory granted for a given request. It is advisable to avoid allocating very small blocks of memory on the heap, as the overhead and alignment considerations may lead to inefficient memory usage. Using realloc to extend memory allocations can be beneficial, as it may allow for free extensions of memory regions. Overall, understanding memory allocation behavior and avoiding unnecessary small allocations can lead to more efficient memory usage in programs.