Function luaL_addvalue

3rd/lua-5.4.3/src/lauxlib.c:618–626

** 'luaL_addvalue' is the only function in the Buffer system where the ** box (if existent) is not on the top of the stack. So, instead of ** calling 'luaL_addlstring', it replicates the code using -2 as the ** last argument to 'prepbuffsize', signaling that the box is (or will ** be) bellow the string being added to the buffer. (Box creation can ** trigger an emergency GC, so we should not remove

** stack before we have the space guaranteed.)
*/
LUALIB_API void luaL_addvalue (luaL_Buffer *B) {
  lua_State *L = B->L;
  size_t len;
  const char *s = lua_tolstring(L, -1, &len);
  char *b = prepbuffsize(B, len, -2);
  memcpy(b, s, len * sizeof(char));
  luaL_addsize(B, len);
  lua_pop(L, 1);  /* pop string */
}


LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {