因为不仅仅信号量，共享内存、消息队列在NDK下都不能用，所以之前使用Linux 下IPC的消息队列，msgget/msgsnd/msgrcv都不能使用，所以没有办法，只能自己实现消息队列，采用linux 下互斥锁和条件变量实现了读时-队列空-会阻塞，写时-队列满-会阻塞。
talk is easy, show me the code. -- 废话少说，放码过来。编译时候使用 cc main.c -pthread，注意-pthread参数，因为依赖线程库。
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#include <stdio.h>
#include <pthread.h>
#include <string.h>
#include <stdlib.h>
#include<sys/time.h>
#define MAX_QUEUE_SIZE_IN_BYTES (1024)
#define MQ_SIZE_MAX 512
#define MQ_LENGTH_MAX 30
#define MQ_NAME "msg queue example"
typedef struct _simple_queue
{
int front;
int rear;
int length;
int queue_type;
pthread_mutex_t data_mutex;
pthread_cond_t data_cond;
int write_pos;
char queue_name[32];
void *data[0];
}simple_queue;
typedef enum _queue_type
{
QUEUE_BLOCK = 0,
QUEUE_NO_BLOCK,
}queue_type;
typedef enum _queue_status
{
QUEUE_IS_NORMAL = 0,
QUEUE_NO_EXIST,
QUEUE_IS_FULL,
QUEUE_IS_EMPTY,
}queue_status;
typedef enum _cntl_queue_ret
{
CNTL_QUEUE_SUCCESS = 0,
CNTL_QUEUE_FAIL,
CNTL_QUEUE_TIMEOUT,
CNTL_QUEUE_PARAM_ERROR,
}cntl_queue_ret;
typedef enum _queue_flag
{
IPC_BLOCK = 0,
IPC_NOWAIT = 1,
IPC_NOERROR = 2,
}queue_flag;
typedef struct _simple_queue_buf
{
int msg_type;
char msg_buf[50];
}queue_buf;
simple_queue* create_simple_queue(const char* queue_name, int queue_length, int queue_type)
{
simple_queue *this = NULL;
if (NULL == queue_name || 0 == queue_length)
{
printf("[%s] param is error\n", __FUNCTION__);
return NULL;
}
if(queue_length > MAX_QUEUE_SIZE_IN_BYTES)
{
printf("[%s] param is error,queue_length should less than %d bytes\n", __FUNCTION__, MAX_QUEUE_SIZE_IN_BYTES);
return NULL;
}
this = (simple_queue*)malloc(sizeof(simple_queue) + queue_length * sizeof(void*));
if (NULL != this)
{
this->front = 0;
this->rear = 0;
this->length = queue_length;
this->queue_type = queue_type;
if (0 != pthread_mutex_init(&(this->data_mutex), NULL) || 0 != pthread_cond_init(&(this->data_cond), NULL))
{
printf("[%s]pthread_mutex_init failed!\n", __FUNCTION__);
free(this);
this = NULL;
return NULL;
}
strcpy(this->queue_name, queue_name);
}
else
{
printf("[%s]malloc is failed!\n", __FUNCTION__);
return NULL;
}
return this;
}
queue_status is_full_queue(simple_queue* p_queue)
{
queue_status ret = QUEUE_IS_NORMAL;
do
{
if (NULL == p_queue)
{
printf("[%s] param is error\n", __FUNCTION__);
ret = QUEUE_NO_EXIST;
break;
}
if (p_queue->front == ((p_queue->rear + 1) % (p_queue->length)))
{
printf("[%s] queue is full\n", __FUNCTION__);
ret = QUEUE_IS_FULL;
break;
}
}while(0);
return ret;
}
queue_status is_empty_queue(simple_queue* p_queue)
{
queue_status ret = QUEUE_IS_NORMAL;
do
{
if (NULL == p_queue)
{
printf("[%s] param is error\n", __FUNCTION__);
ret = QUEUE_NO_EXIST;;
break;
}
if (p_queue->front == p_queue->rear)
{
printf("[%s] queue is empty\n", __FUNCTION__);
ret = QUEUE_IS_EMPTY;
break;
}
}while(0);
return ret;
}
cntl_queue_ret push_simple_queue(simple_queue* p_queue, void* data, queue_flag flg)
{
int w_cursor = 0;
if(NULL == p_queue || NULL == data)
{
printf("[%s] param is error\n", __FUNCTION__);
return CNTL_QUEUE_PARAM_ERROR;
}
pthread_mutex_lock(&(p_queue->data_mutex));
w_cursor = (p_queue->rear + 1)%p_queue->length;
if (w_cursor == p_queue->front)
{
if(flg == IPC_BLOCK)
{
pthread_cond_wait(&(p_queue->data_cond), &(p_queue->data_mutex));
}
else
{
printf("[%s]: queue is full\n", __FUNCTION__);
pthread_mutex_unlock(&(p_queue->data_mutex));
return CNTL_QUEUE_FAIL;
}
w_cursor = (p_queue->rear + 1)%p_queue->length;
}
p_queue->data[p_queue->rear] = data;
p_queue->rear = w_cursor;
pthread_mutex_unlock(&(p_queue->data_mutex));
pthread_cond_signal(&(p_queue->data_cond));
return CNTL_QUEUE_SUCCESS;
}
cntl_queue_ret pop_simple_queue(simple_queue* p_queue, void** data, queue_flag flg)
{
if(NULL == p_queue)
{
printf("[%s] param is error\n", __FUNCTION__);
return CNTL_QUEUE_PARAM_ERROR;
}
pthread_mutex_lock(&(p_queue->data_mutex));
if (p_queue->front == p_queue->rear)
{
if(flg == IPC_BLOCK)
{
pthread_cond_wait(&(p_queue->data_cond), &(p_queue->data_mutex));
}
else
{
printf("[%s]: queue is empty\n", __FUNCTION__);
pthread_mutex_unlock(&(p_queue->data_mutex));
return CNTL_QUEUE_FAIL;
}
}
*data = p_queue->data[p_queue->front];
p_queue->front = (p_queue->front + 1)%p_queue->length;
pthread_mutex_unlock(&(p_queue->data_mutex));
pthread_cond_signal(&(p_queue->data_cond));
return CNTL_QUEUE_SUCCESS;
}
cntl_queue_ret destroy_simple_queue(simple_queue* p_queue)
{
cntl_queue_ret ret = CNTL_QUEUE_SUCCESS;
if(NULL == p_queue)
{
printf("[%s] param is error\n", __FUNCTION__);
ret = CNTL_QUEUE_PARAM_ERROR;
}
else
{
pthread_mutex_destroy(&(p_queue->data_mutex));
pthread_cond_destroy(&(p_queue->data_cond));
while (p_queue->front != p_queue->rear)//删除队列中残留的消息
{
free(p_queue->data[p_queue->front]);
p_queue->front = (p_queue->front + 1)%p_queue->length;
}
free(p_queue);
p_queue = NULL;
}
return ret;
}
void* send_msg_thread(void* arg)
{
queue_buf* send_buf = NULL;
int i;
send_buf = (queue_buf*)malloc(sizeof(queue_buf));
send_buf->msg_type = 1;
strcpy(send_buf->msg_buf, "hello, world!");
printf("first1: rear =%d font =%d\n", ((simple_queue*)arg)->rear, ((simple_queue*)arg)->front);
if (push_simple_queue((simple_queue*)arg, (void*)send_buf, IPC_BLOCK) < 0)
{
printf("[%s]: push_simple_queue\n", __FUNCTION__);
return NULL;
}
printf("first2: rear =%d font =%d\n", ((simple_queue*)arg)->rear, ((simple_queue*)arg)->front);
queue_buf* send_buf1 = NULL;
send_buf1 = (queue_buf*)malloc(sizeof(queue_buf));
send_buf1->msg_type = 2;
strcpy(send_buf1->msg_buf, "byebye");
printf("first1: rear =%d font =%d\n", ((simple_queue*)arg)->rear, ((simple_queue*)arg)->front);
if (push_simple_queue((simple_queue*)arg, (void*)send_buf1, IPC_NOWAIT) < 0)
{
printf("[%s]: push_simple_queue\n", __FUNCTION__);
return NULL;
}
printf("first2: rear =%d font =%d\n", ((simple_queue*)arg)->rear, ((simple_queue*)arg)->front);
return NULL;
}
void* recv_msg_thread(void* arg)
{
int i;
queue_buf* recv_buf = (queue_buf*)malloc(sizeof(queue_buf));
printf("second1 rear =%d font =%d\n", ((simple_queue*)arg)->rear, ((simple_queue*)arg)->front);
if (CNTL_QUEUE_SUCCESS != pop_simple_queue((simple_queue*)arg, (void**)&recv_buf, IPC_BLOCK))
{
printf("[%s]: pop_simple_queue failed!\n", __FUNCTION__);
return NULL;
}
for(i=0; i<50; i++)
printf("%c", recv_buf->msg_buf[i]);
printf("\r\n");
printf("second2: rear =%d font =%d\n", ((simple_queue*)arg)->rear, ((simple_queue*)arg)->front);
printf("second1: rear =%d font =%d\n", ((simple_queue*)arg)->rear, ((simple_queue*)arg)->front);
if (CNTL_QUEUE_SUCCESS != pop_simple_queue((simple_queue*)arg, (void**)&recv_buf, IPC_NOWAIT))
{
printf("[%s]: pop_simple_queue failed!\n", __FUNCTION__);
return NULL;
}
for(i=0; i<50; i++)
printf("%c", recv_buf->msg_buf[i]);
printf("\r\n");
printf("second2: rear =%d font =%d\n", ((simple_queue*)arg)->rear, ((simple_queue*)arg)->front);
free(recv_buf);
recv_buf = NULL;
return NULL;
}
int main(int argc, char* argv[])
{
int ret = 0;
pthread_t send_thread_id = 0;
pthread_t recv_thread_id = 0;
simple_queue* msg_queue = NULL;
msg_queue = create_simple_queue(MQ_NAME, MQ_LENGTH_MAX, QUEUE_NO_BLOCK);
if (NULL == msg_queue)
{
printf("[%s]: create simple queue failed!\n", __FUNCTION__);
return -1;
}
ret = pthread_create(&send_thread_id, NULL, send_msg_thread, (void*)msg_queue);
if (0 != ret)
{
printf("[%s]: create send thread failed!\n", __FUNCTION__);
return -1;
}
ret = pthread_create(&recv_thread_id, NULL, recv_msg_thread, (void*)msg_queue);
if (0 != ret)
{
printf("[%s]: create recv thread failed!\n", __FUNCTION__);
return -1;
}
printf("begin join\n");
pthread_join(send_thread_id, NULL);
pthread_join(recv_thread_id, NULL);
printf("end join\n");
ret = destroy_simple_queue(msg_queue);
if (CNTL_QUEUE_SUCCESS != ret)
{
printf("[%s]: destroy simple queue failed!\n", __FUNCTION__);
return -1;
}
return 0;
}
