在C中获取Lua表的大小 [英] Get Lua table size in C

问题描述

如何在C语言中获取Lua表的大小?

How can I get a size of a Lua table in C?

static int lstage_build_polling_table (lua_State * L) {
    lua_settop(L, 1);
    luaL_checktype(L, 1, LUA_TTABLE);
    lua_objlen(L,1);
    int len = lua_tointeger(L,1);
    printf("%d\n",len);
    ...
}

我的Lua代码:

local stages = {}
stages[1] = stage1
stages[2] = stage2
stages[3] = stage3

lstage.buildpollingtable(stages)

它总是打印0.我在做什么错了?

It´s printing 0 always. What am I doing wrong?

推荐答案

lua_objlen返回对象的长度，它不会将任何内容压入堆栈.

lua_objlen returns the length of the object, it doesn't push anything on the stack.

即使它确实将某些内容压入堆栈，您的lua_tointeger调用也会使用表的索引，而不是lua_objlen会压入堆栈的任何内容(如果它首先压入任何内容，则不会) t).

Even if it did push something on the stack your lua_tointeger call is using the index of the table and not whatever lua_objlen would have pushed on the stack (if it pushed anything in the first place, which it doesn't).

您想要size_t len = lua_objlen(L,1);用于lua 5.1.

You want size_t len = lua_objlen(L,1); for lua 5.1.

或size_t len = lua_rawlen(L,1);用于lua 5.2.

Or size_t len = lua_rawlen(L,1); for lua 5.2.

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