Function db_num_columns

lua/sp.c:4298–4327

}

static int db_num_columns(Lua L)
{
    luaL_checkudata(L, 1, dbtypes.db);
    int num_cols = luaL_checknumber(L, 2);
    SP sp = getsp(L);
    SP parent = sp->parent;
    struct sqlclntstate *parent_clnt = parent->clnt;
    int num = override_count(parent_clnt);
    if (num && num != num_cols) {
        return luaL_error(
            L, "attempt to change number of columns for typed-statement");
    }
    Pthread_mutex_lock(parent->emit_mutex);
    if (parent_clnt->osql.sent_column_data) {
        Pthread_mutex_unlock(parent->emit_mutex);
        return luaL_error(L, "attempt to change number of columns");
    }
    if (num_cols < parent->ntypes) {
        for (int i = num_cols - 1; i < parent->ntypes; ++i) {
            free(parent->clntname[i]);
            parent->clntname[i] = NULL;
        }
        parent->ntypes = num_cols;
    } else {
        new_col_info(sp, num_cols);
    }
    Pthread_mutex_unlock(parent->emit_mutex);
    lua_pushinteger(L, 0);
    return 1;
}

static int db_reset(lua_State *lua)
{