Concatenates a copy of the contents of src onto the end of dest. Returns 0 if the function succeeded, or -1 if there was insufficient memory.
Concatenates a copy of the len bytes stored at buf onto the end of abuf. len may not be negative. Returns 0 if the function succeeded, or -1 if there was insufficient memory.
Concatenates a copy of the contents of astr onto the end of abuf. Returns 0 if the function succeeded, or -1 if there was insufficient memory.