Host order, network order, observe directly through the debugger

In the history of computer development, there has been no unified standard for data storage

There are two common rules for byte ordering. For example, little-endian refers to arranging the lower digits of a multi-digit number at smaller addresses and the higher digits at larger addresses; conversely, big-endian is when this arrangement is reversed. Byte order is a factor that must be considered in network applications because different machine types may use different standards, so they are all converted according to the network standard.

Big-endian byte order aligns better with the left-to-right reading habit

Please provide the Chinese text you want me to translate. I am ready when you are! Just paste the text here.

Processors such as x86, MOS Technology 6502, Z80, VAX, and PDP-11 are little-endian
Processors such as Motorola 6800, Motorola 68000, and PowerPC 970 use big-endian order
The byte order for ARM, PowerPC (excluding PowerPC 970), DEC Alpha, SPARC V9, MIPS, PA-RISC, and IA64 is configurable

Network Preface

Network transmission generally uses big-endian order, also known as network byte order or network order. Big-endian is defined as the network byte order in the IP protocol. Socket definitions specify a set of conversion functions for transforming 16- and 32-bit integers between network byte order and host byte order

#include <arpa/inet.h>

uint32_t htonl(uint32_t hostlong); //把uint32_t类型从主机序转换到网络序
uint16_t htons(uint16_t hostshort); //把uint16_t类型从主机序转换到网络序
uint32_t ntohl(uint32_t netlong); //把uint32_t类型从网络序转换到主机序
uint16_t ntohs(uint16_t netshort); //把uint16_t类型从网络序转换到主机序

If INLIN_ITALIC_1__ is chosen as the network library, the built-in namespace contains cross-platform adapted function names

boost::asio::detail::socket_ops::network_to_host_long
boost::asio::detail::socket_ops::network_to_host_short
boost::asio::detail::socket_ops::host_to_network_long
boost::asio::detail::socket_ops::host_to_network_short

Visual Studio debugger

In debug mode, select the Debug menu, then Window, and check Memory Window

In INLIN_ITALIC_1__, you can view data in memory directly within the debugger, as shown in the figure below

Please provide the Chinese text you want me to translate. I am ready when you are.

How to check memory

Prints the variable name and jumps to its address
If the variable is already a pointer, select it by double-clicking, drag it to the memory window, and display the contents at that address
If the variable is not a pointer, add it to the calculation window, obtain its address, then manually copy it to the memory window

For example

Received data, stored in INLINE_CODE_0__对象中，将网络序转成主机序，得到__INLINE_CODE_1 equal to 30, and the server allocates four bytes for transmitting this data

bool NetworkMessage::decode_header()
{
    // 网络序转成主机序
    body_length_ = boost::asio::detail::socket_ops::network_to_host_long(*(int *)buffer_.data());
    return auto_reserve(body_length_);
}

Observe the content of INLINE_CODE_0 in the memory window

buffer_

Observe the content of INLINE_CODE_0 in the memory window

body_length_