Question

typedef const char * (*lua_Reader) (lua_State *L,
 void *data,
 size_t *size);

The reader function used by lua_load. Every time it needs another piece of the chunk, lua_load calls the reader, passing along its data parameter. The reader must return a pointer to a block of memory with a new piece of the chunk and set size to the block size. The block must exist until the reader function is called again. To signal the end of the chunk, the reader must return NULL. The reader function may return pieces of any size greater than zero.