/*

* Description: lock free queue, for mulit process or thread read and write

* History: [email protected], 2013/03/06, create

*/

# pragma once

# ifdef __cplusplus

extern "C" {

# endif

# include <stdint.h>

# include <sys/types.h>

typedef void * lf_queue;

/*

* pragma:

* shm_key: 不为 0 使用共享内存，否则使用 malloc 获取内存

* unit_size: 数据单元长度

* max_unit_num: 队列最大长度

* return:

* < 0: error

* == 0: success

*/

int lf_queue_init(lf_queue *queue, key_t shm_key, int32_t unit_size, int32_t max_unit_num);

/*

* return:

* < -1: error

* == -1: full

* == 0: success

*/

int lf_queue_push(lf_queue queue, void *unit);

/*

* return:

* < -1: error

* == -1: empty

* == 0: success

*/

int lf_queue_pop(lf_queue queue, void *unit);

/*

* return:

* < 0: error

* >= 0: len

*/

int lf_queue_len(lf_queue queue);

# ifdef __cplusplus

}

# endif