Reallocates the memory pointed to by mem, so that it now has space for
n_bytes bytes of memory. It returns the new address of the memory, which may
have been moved. mem may be NULL, in which case it's considered to
have zero-length. n_bytes may be 0, in which case NULL will be returned
and mem will be freed unless it is NULL.
Reallocates the memory pointed to by mem, so that it now has space for n_bytes bytes of memory. It returns the new address of the memory, which may have been moved. mem may be NULL, in which case it's considered to have zero-length. n_bytes may be 0, in which case NULL will be returned and mem will be freed unless it is NULL.