linux网络传输float类型，大小端转换问题

需要传输的数据如下：

float volume = 0.9876;

char send_buff[1024] = {0};
int send_len = 0;

一、发送端数据处理

###错误示例如下###

错误1.
float tmp = 0.0;

tmp = htonl(volume);

memcpy(send_buff, &tmp, sizeof(tmp));
send_len += sizeof(tmp);


错误2.
uint32_t tmp = 0;

tmp = htonl(volume);

memcpy(send_buff, &tmp, sizeof(tmp));
send_len += sizeof(tmp);

###正确示例如下###

uint32_t tmp = 0;

memcpy(&tmp, &volume, sizeof(volume));

tmp = htonl(tmp);

memcpy(send_buff, &tmp, sizeof(tmp));
send_len += sizeof(tmp);

二、接收端数据处理

###错误示例如下###

错误1.
float tmp = 0.0;

memcpy(&tmp, send_buff, sizeof(tmp));

tmp = ntohl(volume);




错误2.
uint32_t tmp = 0;
float volume_recv = 0.0;

memcpy(&tmp, send_buff, sizeof(tmp));

volume_recv = ntohl(tmp);

###正确示例如下###

uint32_t tmp = 0;
float volume_recv = 0.0;

memcpy(&tmp, send_buff, sizeof(tmp));

tmp = ntohl(tmp);

memcpy(&volume_recv, &tmp, sizeof(volume_recv);