Problem when copying memory

Question

So there is a problem I am headbanging over two nights in a row:

(tuple1 and tuple2 are void pointers passed to this function)

char *data;

data = (char*         


        

Answer 1

Begin your experiment with something smaller, which is easier to debug:

void* tuple1 = calloc(2, 1);
char* content1 = "ab";
memcpy(tuple1, content1, 2);

void* tuple2 = calloc(4, 1);
char* content2 = "cdef";;
memcpy(tuple2, content2, 4);

char *data = data = (char*) calloc (6, 1);
memcpy(data, tuple1, 2);
memcpy(data+2, tuple2, 4);

printf("%.*s\n", 6, data); // should print: abcdef

Answer 2

I would suspect issues with alignment and/or padding, what are the type declarations of tuple1 and tuple2?

How do you know their exact sizes? Code that hardcodes things is suspect, there should be some use of sizeof rather than magic number literals.

Also, you shouldn't cast the return value of calloc(), in C.