Why does my structure assignment fail in C language？ - objective-c

Question

Why does my structure assignment fail in C language？
I have a class A: define a structure
typedef struct{
int sockfd;
on_av_frame_cb av_frame_cb;
on_av_frame_cb rtp_cb;
on_error_cb error_cb;
uint8_t *p_buf;
uint8_t *v_buf;
uint8_t *a_buf;
int rtp_flag;
}udp_client_t;
Then I call in class B:
static udp_client_t client;
int jldv_create_client(int src_port,int port ,const char *dst_ip){
udp_client_t *udpClient = &client;
assert(udpClient != NULL);
const char *c_ip = dst_ip;
memset(udpClient, 0, sizeof(udp_client_t));
int ret = create_client(src_port, port, c_ip, &udpClient);
if (ret != 0) {
goto err_output;
}
udpClient->av_frame_cb = (on_av_frame_cb )onVideoFrame;
udpClient->error_cb = on_error;
if (rtp_create(&udpClient) < 0) { ///above problem
goto err_output;
}
printf("rtp_client:%d \n",udpClient->rtp_flag);
return 0;
err_output:
destroy_client(udpClient);
return -1;
}
In the above problem, I used the C class method:
int rtp_create(udp_client_t **data)
{
logi("%s", __func__);
udp_client_t *udpClient = *data;
if(udpClient)
{
udpClient->rtp_flag = 1;
memset(&rtp_cxt, 0, sizeof(rtp_context_t));
int ret = init_server();
if (ret < 0)
{
return -1;
}
rtp_cxt.nalu = alloc_nalu(MAX_FRAME_SIZE);//
if (!rtp_cxt.nalu)
{
loge("alloc nalu failed");
return -2;
}
}
else
{
loge("%s: data is null", __func__);
return -3;
}
printf("udpClient after==>%d \n",udpClient->rtp_flag);
return 0;
}
However, the result of printing is:
udpClient after==>1
rtp_client:0
supplement:
int create_client(int src_port, int dst_port, const char *dst_ip, udp_client_t **client)
{
udp_client_t *udpClient = *client;
assert(udpClient != NULL);
memset(udpClient, 0, sizeof(udp_client_t));
printf("create_client:%p\n",udpClient);
udpClient->port = src_port;
if (pthread_create(&udpClient->recv_tid, NULL, udp_receiver_runnable, (void *) udpClient) != 0)
{
loge("Failed to start new thread");
goto err_output;
}
return 0;
err_output:
memset(udpClient, 0, sizeof(udp_client_t));
return -10;
}
Why is that? Did i use something wrong?