静态的声明一个指针变量

我是从Android的GPS模拟器代码中看到的，觉得很有意思，就记录下来了

首先是结构体的定义：

[cpp]
/* this is the state of our connection to the qemu_gpsd daemon */
typedef struct {
    int                     init;
    int                     fd;
    GpsCallbacks            callbacks;
    pthread_t               thread;
    int                     control[2];
} GpsState;

/* this is the state of our connection to the qemu_gpsd daemon */
typedef struct {
    int                     init;
    int                     fd;
    GpsCallbacks            callbacks;
    pthread_t               thread;
    int                     control[2];
} GpsState;
然后声明结构体指针变量

static GpsState _gps_state[1];

正常使用：

[cpp]
static int
qemu_gps_init(GpsCallbacks* callbacks)
{
    GpsState* s = _gps_state;

    if (!s->init)
        gps_state_init(s, callbacks);

    if (s->fd < 0)
        return -1;

    return 0;
}

static int
qemu_gps_init(GpsCallbacks* callbacks)
{
GpsState* s = _gps_state;

if (!s->init)
gps_state_init(s, callbacks);

if (s->fd < 0)
return -1;

return 0;
}

补充：软件开发 , C++ ,