在哈希映射中将结构用作键。如何插入值?

代码在编译行失败

    map_free_segments [ loc ] = color;

错误的第一行是:
错误C2784:“bool std::operator<(const std::vector<_ty,_alloc>&,const std::vector<_ty,_alloc>&)”:无法从“const本地化”中推导“const std::vector<_alloc>&”的模板参数。

完整来源:

#include <windows.h>

#include <hash_map>
using namespace std;
using namespace stdext;

#pragma pack(1)
struct localization
{
    char X;
    char Y;
    char Z;
    char L;
};
#pragma pack(1)

typedef hash_map<localization,unsigned long> type_map_free_segments;

//typedef pair<localization, unsigned long> pair_loc;


int main(int argc, CHAR* argv[])
{
    unsigned long color = 1234;
    type_map_free_segments map_free_segments;

    localization loc;

    loc.X = 1;
    loc.Y = 2;
    loc.Z = 3;
    loc.L = 5;

    map_free_segments [ loc ] = color;
    //map_free_segments.insert( pair_loc(loc, color ));

    return 0;
}