NET

Overview

Provides functions and data structures related to network operations.

Since:

1.0

Version:

1.0

Summary

Files

File Name

Description

inet.h

Provides functions and data structures related to network operations.

ifaddrs.h

Provides functions and data structures related to network operations.

if.h

Provides functions and data structures related to network operations. For example, you can use the functions to send and receive network data, manage network addresses, and convert bytes.

netdb.h

Provides functions and data structures related to network operations. For example, you can use the functions to send and receive network data, manage network addresses, and convert bytes.

ether.h

Provides functions and data structures related to network operations. For example, you can use the functions to send and receive network data, manage network addresses, and convert bytes.

resolv.h

Provides functions and data structures related to network operations. For example, you can use the functions to send and receive network data, manage network addresses, and convert bytes.

socket.h

Provides functions and data structures related to network operations.

Data Structures

Data Structure Name

Description

ifaddrs

Defines the network interface information.

if_nameindex

Defines the network adapter information.

hostent

Describes the host name and address information.

sockaddr

Describes the socket address information.

Macros

Macro Name and Value

Description

h_addr    h_addr_list[0]

Defines the first address in h_addr_list for backward compatibility.

SOL_SOCKET    1

Defines options for socket level.

Functions

Function Name

Description

htonl (uint32_t n)

uint32_t 

Converts an integer from the host byte order to the network byte order.

htons (uint16_t n)

uint16_t 

Converts a 16-bit integer from the host byte order to the network byte order.

ntohl (uint32_t n)

uint32_t 

Converts an integer from the network byte order to the host byte order.

ntohs (uint16_t n)

uint16_t 

Converts a 16-bit integer from the network byte order to the host byte order.

inet_addr (const char p)

in_addr_t 

Converts a string from the IPv4 numbers-and-dots notation to the binary data in network byte order.

inet_network (const char p)

in_addr_t 

Converts a string from the IPv4 numbers-and-dots notation to the binary data in host byte order.

inet_ntoa (struct in_addr in)

char  

Converts a network address to a string in dotted-decimal format.

inet_pton (int af, const char restrict s, void *restrict a0)

int 

Converts a string to a network address in the specified address family.

inet_ntop (int af, const void restrict a0, char restrict s, socklen_t l)

const char  

Converts a network address in the specified address family to a string.

inet_aton (const char s0, struct in_addr dest)

int 

Converts an IP address from the string format to the 32-bit binary format in network byte order.

inet_makeaddr (in_addr_t n, in_addr_t h)

struct in_addr 

Converts the network number and host address to the network address.

inet_lnaof (struct in_addr in)

in_addr_t 

Converts an IP address into a host ID in host byte order without network bits.

inet_netof (struct in_addr in)

in_addr_t 

Extracts the network number from the in_addr structure and converts it to the host byte order.

freeifaddrs (struct ifaddrs ifp)

void 

Frees the network interface information obtained by getifaddrs.

if_freenameindex (struct if_nameindexidx)

void 

Frees the network adapter information obtained by if_nameindex.

setprotoent (int stayopen)

void 

Opens a connection to the database and sets the next entry to the first entry.

getprotoent (void)

struct protoent  

Retrieves the current protocol information.

getprotobyname (const char name)

struct protoent  

Retrieves the information about a specified protocol.

getprotobynumber (int num)

struct protoent  

Retrieves the information about a protocol with the specified number.

herror (const char msg)

void 

Prints error information.

hstrerror (int ecode)

const char  

Retrieves error information associated with the specified error number.

ether_ntoa (const struct ether_addr p_a)

char  

Converts binary data in network byte order into a standard 48-bit Ethernet host address in the colon hexadecimal notation.

ether_aton (const char x)

struct ether_addr  

Converts a standard 48-bit Ethernet host address in the colon hexadecimal notation into binary data in network byte order.

ether_ntoa_r (const struct ether_addr p_a, char x)

char  

Converts binary data in network byte order into a standard 48-bit Ethernet host address in the colon hexadecimal notation. This function is reentrant.

ether_aton_r (const char x, struct ether_addr p_a)

struct ether_addr  

Converts a standard 48-bit Ethernet host address in the colon hexadecimal notation into binary data in network byte order. This function is reentrant.

dn_comp (const char src, unsigned char dst, int space, unsigned char dnptrs, unsigned char lastdnptr)

int 

Compresses a network domain name.

dn_expand (const unsigned char base, const unsigned char end, const unsigned char src, char dest, int space)

int 

Expands a compressed domain name to a full domain name.

socket (int domain, int type, int protocol)

int 

Creates a socket and returns its descriptor.

shutdown (int sockfd, int how)

int 

Shuts down a socket.

bind (int sockfd, const struct sockaddr addr, socklen_t addrlen)

int 

Binds a local protocol address to a socket.

connect (int sockfd, const struct sockaddraddr, socklen_t addrlen)

int 

Initiates a connection to a socket.

listen (int sockfd, int backlog)

int 

Listens for network connections.

accept (int sockfd, struct sockaddrrestrict addr, socklen_t *restrict addrlen)

int 

Accepts incoming connection requests.

getsockname (int fd, struct sockaddrrestrict addr, socklen_t restrict len)

int 

Retrieves the local address of the specified socket.

getpeername (int fd, struct sockaddrrestrict addr, socklen_t restrict len)

int 

Retrieves the peer address of the specified socket.

send (int fd, const void buf, size_t len, int flags)

ssize_t 

Sends data to another socket.

recv (int fd, void buf, size_t len, int flags)

ssize_t 

Receives data from another socket.

sendto (int fd, const void buf, size_t len, int flags, const struct sockaddraddr, socklen_t alen)

ssize_t 

Sends data to another socket.

recvfrom (int fd, void __restrict buf, size_t len, int flags, struct sockaddrrestrict addr, socklen_t *restrict alen)

ssize_t 

Receives data from a specified socket.

sendmsg (int fd, const struct msghdr msg, int flags)

ssize_t 

Sends data to another socket.

recvmsg (int fd, struct msghdr msg, int flags)

ssize_t 

Receives data from a specified socket.

getsockopt (int fd, int level, int optname, void __restrict optval, socklen_t __restrict optlen)

int 

Retrieves the socket options.

setsockopt (int fd, int level, int optname, const void *optval, socklen_t optlen)

int 

Sets the socket options.

Details

Function Documentation

accept()

  1. int accept (int sockfd,struct[sockaddr]($api-api-SmartVision-Devices-sockaddr.md)*__restrict addr,socklen_t*__restrict addrlen )

Description:

Accepts incoming connection requests.

Parameters:

Name

Description

sockfdIndicates the socket descriptor.
addrIndicates the pointer to the socket address requiring for the connection.
addrlenIndicates the length of the address structure pointed to by addr.

Returns:

Returns a valid socket if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EOPNOTSUPP

The socket requiring for the connection is not of the NETCONN_TCP type.

EWOULDBLOCK

Failure to receive events in non-blocking mode.

ENFILE

Failure to creat a new socket.

ECONNABORTED

Failure to receive the remote information.

ENOMEM

Memory copy exception.

bind()

  1. int bind (int sockfd,conststruct[sockaddr]($api-api-SmartVision-Devices-sockaddr.md)* addr,socklen_t addrlen )

Description:

Binds a local protocol address to a socket.

Parameters:

Name

Description

sockfdIndicates the socket descriptor.
addrIndicates the address to be bound to the socket.
addrlenIndicates the length of the address structure pointed to by addr.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

connect()

  1. int connect (int sockfd,conststruct[sockaddr]($api-api-SmartVision-Devices-sockaddr.md)* addr,socklen_t addrlen )

Description:

Initiates a connection to a socket.

Parameters:

Name

Description

sockfdIndicates the socket descriptor.
addrIndicates the pointer to the address to be connected.
addrlenIndicates the length of the address structure pointed to by addr.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

EIO

Incorrect connection type obtained based on the socket descriptor

ECONNREFUSED

Restart due to connection failure

ECONNABORTED

Shut-down due to connection failure

dn_comp()

  1. int dn_comp (constchar* src,unsignedchar* dst,int space,unsignedchar** dnptrs,unsignedchar** lastdnptr )

Description:

Compresses a network domain name.

To reduce the size of DNS messages, domain names in the messages are compressed. For details about the compression scheme, see RFC 1035.

Parameters:

Name

Description

srcIndicates the pointer to the domain name to be compressed.
dstIndicates the pointer to the compressed domain name.
spaceIndicates the size of the compressed domain name.
dnptrsIndicates the pointer to an array of pointers to previously compressed domain names. If the value is NULL, the current domain name will not be compressed.
lastdnptrIndicates the pointer to the last element of the array. If the value is NULL, the array is not updated.

Returns:

Returns the length of the compressed domain name if the operation is successful; returns -1 otherwise.

dn_expand()

  1. int dn_expand (constunsignedchar*base,constunsignedchar*end,constunsignedchar* src,char* dest,int space )

Description:

Expands a compressed domain name to a full domain name.

The compressed domain name is contained in a query or reply message.

Parameters:

Name

Description

baseIndicates the pointer to the start of the DNS message body.
endIndicates the pointer to the end of the DNS message body.
srcIndicates the pointer to the compressed domain name.
destIndicates the pointer to the expanded domain name.
spaceIndicates the memory size of the dest address.

Returns:

Returns the length of the compressed domain name if the operation is successful; returns -1 otherwise.

ether_aton()

  1. struct ether_addr* ether_aton (constchar* x)

Description:

Converts a standard 48-bit Ethernet host address in the colon hexadecimal notation into binary data in network byte order.

Parameters:

Name

Description

xIndicates the pointer to the host address to be converted.

Returns:

Returns the binary data if the operation is successful; returns 0 otherwise.

ether_aton_r()

  1. struct ether_addr* ether_aton_r (constchar* x,struct ether_addr * p_a )

Description:

Converts a standard 48-bit Ethernet host address in the colon hexadecimal notation into binary data in network byte order. This function is reentrant.

This function is used in multitasking scenarios.

Parameters:

Name

Description

xIndicates the pointer to the host address to be converted.
p_aIndicates the pointer to the temporary buffer during conversion.

Returns:

Returns the binary data represented by ether_addr if the operation is successful; returns 0 otherwise.

ether_ntoa()

  1. char* ether_ntoa (conststruct ether_addr * p_a)

Description:

Converts binary data in network byte order into a standard 48-bit Ethernet host address in the colon hexadecimal notation.

Parameters:

Name

Description

p_aIndicates the pointer to the binary data to be converted.

Attention:

Different from glibc (for example, 1:2:3:4:5:f), 0 is prefixed and letters are capitalized (for example, 01:02:03:04:05:0F).

Returns:

Returns the host address if the operation is successful; returns 0 otherwise.

ether_ntoa_r()

  1. char* ether_ntoa_r (conststruct ether_addr * p_a,char* x )

Description:

Converts binary data in network byte order into a standard 48-bit Ethernet host address in the colon hexadecimal notation. This function is reentrant.

This function is used in multitasking scenarios.

Parameters:

Name

Description

p_aIndicates the pointer to the binary data to be converted.
xIndicates the pointer to the temporary buffer during conversion.

Attention:

Different from glibc (for example, 1:2:3:4:5:f), 0 is prefixed and letters are capitalized (for example, 01:02:03:04:05:0F).

Returns:

Returns the host address if the operation is successful; returns 0 otherwise.

freeifaddrs()

  1. void freeifaddrs (struct[ifaddrs]($api-api-SmartVision-Devices-ifaddrs.md)* ifp)

Description:

Frees the network interface information obtained by getifaddrs.

Parameters:

Name

Description

ifpIndicates the pointer to the network interface information to be freed.

getpeername()

  1. int getpeername (int fd,struct[sockaddr]($api-api-SmartVision-Devices-sockaddr.md)*restrict addr,socklen_t*restrict len )

Description:

Retrieves the peer address of the specified socket.

Parameters:

Name

Description

fdIndicates the socket descriptor.
addrIndicates the pointer to the address to be retrieved.
lenIndicates the pointer to the length of the address pointed to by addr.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

ENOMEM

Memory copy exception

getprotobyname()

  1. struct protoent* getprotobyname (constchar* name)

Description:

Retrieves the information about a specified protocol.

Parameters:

Name

Description

addrIndicates the pointer to the protocol name.

Attention:

The /etc/protocols configuration file is not supported. Only the following built-in protocols are supported: ip/icmp/igmp/ggp/ipencap/st/tcp/egp/pup/udp/hmp/xns-idp/rdp/iso-tp4/xtp/ ddp/idpr-cmtp/ipv6/ipv6-route/ipv6-frag/idrp/rsvp/gre/esp/ah/skip/ipv6-icmp/ ipv6-nonxt/ipv6-opts/rspf/vmtp/ospf/ipip/encap/pim/raw (This protocol does not have the aliases attribute, that is, aliases is empty.)

Returns:

Returns the protocol information if the operation is successful; returns NULL otherwise.

getprotobynumber()

  1. struct protoent* getprotobynumber (int num)

Description:

Retrieves the information about a protocol with the specified number.

Parameters:

Name

Description

numIndicates the protocol number.

Attention:

The /etc/protocols configuration file is not supported. Only the following built-in protocols are supported: ip/icmp/igmp/ggp/ipencap/st/tcp/egp/pup/udp/hmp/xns-idp/rdp/iso-tp4/xtp/ ddp/idpr-cmtp/ipv6/ipv6-route/ipv6-frag/idrp/rsvp/gre/esp/ah/skip/ipv6-icmp/ ipv6-nonxt/ipv6-opts/rspf/vmtp/ospf/ipip/encap/pim/raw (This protocol does not have the aliases attribute, that is, aliases is empty.)

Returns:

Returns the protocol information if the operation is successful; returns NULL otherwise.

getprotoent()

  1. struct protoent* getprotoent (void)

Description:

Retrieves the current protocol information.

Attention:

The /etc/protocols configuration file is not supported. Only the following built-in protocols are supported: ip/icmp/igmp/ggp/ipencap/st/tcp/egp/pup/udp/hmp/xns-idp/rdp/iso-tp4/xtp/ ddp/idpr-cmtp/ipv6/ipv6-route/ipv6-frag/idrp/rsvp/gre/esp/ah/skip/ipv6-icmp/ ipv6-nonxt/ipv6-opts/rspf/vmtp/ospf/ipip/encap/pim/raw (This protocol does not have the aliases attribute, that is, aliases is empty.)

Returns:

Returns the protocol information if the operation is successful; returns NULL otherwise.

getsockname()

  1. int getsockname (int fd,struct[sockaddr]($api-api-SmartVision-Devices-sockaddr.md)*restrict addr,socklen_t*restrict len )

Description:

Retrieves the local address of the specified socket.

Parameters:

Name

Description

fdIndicates the socket descriptor.
addrIndicates the pointer to the address to be retrieved.
lenIndicates the pointer to the length of the address pointed to by addr.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

ENOMEM

Memory copy exception

getsockopt()

  1. int getsockopt (int fd,int level,int optname,void*__restrict optval,socklen_t*__restrict optlen )

Description:

Retrieves the socket options.

Parameters:

Name

Description

fdIndicates the socket descriptor.
levelIndicates the protocol level at which the option resides. Only SOL_SOCKET is supported.
optnameIndicates the socket options to be retrieved, which has the following values:
optvalIndicates the pointer to the option data.
optlenIndicates the pointer to the size of the buffer pointed to by optval.

value

Description

SO_BROADCAST

Permits sending broadcast messages.

SO_RCVTIMEO

Receiving data times out.

SO_RCVBUF

Sets or gets the maximum socket receiving buffer in bytes.

SO_TYPE

Gets the socket type.

SO_DONTROUTE

Prohibits messages from being sent via a gateway.

SO_BINDTODEVICE

Binds this socket to a particular device.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Small optlen

EBADF

Invalid socket or socket status exception

EFAULT

The input parameter is a null pointer.

ENOBUFS

Retrieved length exception

ENOMEM

Memory copy exception

herror()

  1. void herror (constchar* msg)

Description:

Prints error information.

Parameters:

Name

Description

msgIndicates the pointer to the string to be printed together with the error information. This parameter can be null.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Incorrect symbols or parameters

EOVERFLOW

Long item for printing

hstrerror()

  1. constchar* hstrerror (int ecode)

Description:

Retrieves error information associated with the specified error number.

Parameters:

Name

Description

ecodeIndicates the error number.

Returns:

Returns the string representing the error information.

htonl()

  1. uint32_t htonl (uint32_t n)

Description:

Converts an integer from the host byte order to the network byte order.

Parameters:

Name

Description

nIndicates the integer in host byte order.

Returns:

Returns the original data if the system is in big-endian mode; returns the converted data otherwise.

htons()

  1. uint16_t htons (uint16_t n)

Description:

Converts a 16-bit integer from the host byte order to the network byte order.

Parameters:

Name

Description

nIndicates the integer in host byte order.

Returns:

Returns the original data if the system is in big-endian mode; returns the converted data otherwise.

if_freenameindex()

  1. void if_freenameindex (struct[if_nameindex]($api-api-SmartVision-Devices-if_nameindex.md)* idx)

Description:

Frees the network adapter information obtained by if_nameindex.

Parameters:

Name

Description

idxIndicates the pointer to the network adapter to be freed.

inet_addr()

  1. in_addr_t inet_addr (constchar* p)

Description:

Converts a string from the IPv4 numbers-and-dots notation to the binary data in network byte order.

Parameters:

Name

Description

pIndicates the pointer to the string to be converted.

Returns:

Returns the converted data if the operation is successful; returns -1 otherwise.

inet_aton()

  1. int inet_aton (constchar* s0,struct in_addr * dest )

Description:

Converts an IP address from the string format to the 32-bit binary format in network byte order.

Parameters:

Name

Description

s0Indicates the pointer to the IP address to be converted.
destIndicates the pointer to the structure for conversion.

Returns:

Returns 1 if the operation is successful; returns 0 otherwise.

inet_lnaof()

  1. in_addr_t inet_lnaof (struct in_addr in)

Description:

Converts an IP address into a host ID in host byte order without network bits.

Parameters:

Name

Description

inIndicates the network address structure.

Returns:

Returns the converted host address.

inet_makeaddr()

  1. struct in_addr inet_makeaddr (in_addr_t n,in_addr_t h )

Description:

Converts the network number and host address to the network address.

Parameters:

Name

Description

nIndicates the network number.
hIndicates the host address.

Returns:

Returns the converted network address.

inet_netof()

  1. in_addr_t inet_netof (struct in_addr in)

Description:

Extracts the network number from the in_addr structure and converts it to the host byte order.

Parameters:

Name

Description

inIndicates the network address structure.

Returns:

Returns the converted network number.

inet_network()

  1. in_addr_t inet_network (constchar* p)

Description:

Converts a string from the IPv4 numbers-and-dots notation to the binary data in host byte order.

Parameters:

Name

Description

pIndicates the pointer to the string to be converted.

Returns:

Returns the converted data if the operation is successful; returns -1 otherwise.

inet_ntoa()

  1. char* inet_ntoa (struct in_addr in)

Description:

Converts a network address to a string in dotted-decimal format.

Parameters:

Name

Description

inIndicates the network address to be converted.

Returns:

Returns the string.

inet_ntop()

  1. constchar* inet_ntop (int af,constvoid*restrict a0,char*restrict s,socklen_t l )

Description:

Converts a network address in the specified address family to a string.

Parameters:

Name

Description

afIndicates the address family. Currently, only AF_INET and AF_INET6 are supported.
a0Indicates the pointer to the data to be converted.
sIndicates the pointer to the string to be converted.
lIndicates the size of the string to be converted.

Returns:

Returns the converted string if the operation is successful; returns NULL and sets errno to a value in the following table if the operation fails.

errno

Description

ENOSPC

Insufficient space for conversion

EAFNOSUPPORT

Unsupported address family

inet_pton()

  1. int inet_pton (int af,constchar*__restrict s,void*__restrict a0 )

Description:

Converts a string to a network address in the specified address family.

Parameters:

Name

Description

afIndicates the address family. Currently, only AF_INET and AF_INET6 are supported.
sIndicates the pointer to the string to be converted.
a0Indicates the pointer to the converted data.

Returns:

Returns 1 if the operation is successful; returns 0 if the input address family is invalid; returns -1 if the operation fails. The error codes are set as follows:

errno

Description

EAFNOSUPPORT

Unsupported address family

listen()

  1. int listen (int sockfd,int backlog )

Description:

Listens for network connections.

Parameters:

Name

Description

sockfdIndicates the socket descriptor.
backlogIndicates the maximum length of the queue to accept incoming connection requests.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

EIO

Incorrect connection type obtained based on the socket descriptor

ntohl()

  1. uint32_t ntohl (uint32_t n)

Description:

Converts an integer from the network byte order to the host byte order.

Parameters:

Name

Description

nIndicates the integer in network byte order.

Returns:

Returns the original data if the system is in big-endian mode; returns the converted data otherwise.

ntohs()

  1. uint16_t ntohs (uint16_t n)

Description:

Converts a 16-bit integer from the network byte order to the host byte order.

Parameters:

Name

Description

nIndicates the integer in network byte order.

Returns:

Returns the original data if the system is in big-endian mode; returns the converted data otherwise.

recv()

  1. ssize_t recv (int fd,void* buf,size_t len,int flags )

Description:

Receives data from another socket.

Parameters:

Name

Description

fdIndicates the socket descriptor.
bufIndicates the pointer to a buffer for storing the data to be received.
lenIndicates the length of the buffer pointed to by buf.
flagsIndicates the socket flags. This parameter has the following values:

value

Description

MSG_DONTWAIT

Enables the non-blocking operation.

MSG_MORE

The caller has more data to send.

MSG_NOSIGNAL

No signals are generated.

Returns:

Returns the length of the received data if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

ENOMEM

Memory copy exception

EOPNOTSUPP

Unsupported message type

ENOTCONN

Socket not connected

EWOULDBLOCK

Blocking operation

ENOTCONN

Connection closed

recvfrom()

  1. ssize_t recvfrom (int fd,void*__restrict buf,size_t len,int flags,struct[sockaddr]($api-api-SmartVision-Devices-sockaddr.md)*__restrict addr,socklen_t*__restrict alen )

Description:

Receives data from a specified socket.

Parameters:

Name

Description

fdIndicates the socket descriptor.
bufIndicates the pointer to a buffer for storing the data to be received.
lenIndicates the length of the buffer pointed to by buf.
flagsIndicates the socket flags. This parameter has the following values:
addrIndicates the pointer to the source address.
alenIndicates the size of the source address.

value

Description

MSG_DONTWAIT

Enables the non-blocking operation.

MSG_MORE

The caller has more data to send.

MSG_NOSIGNAL

No signals are generated.

Returns:

Returns the length of the received data if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

ENOMEM

Memory copy exception

EOPNOTSUPP

Unsupported message type

ENOTCONN

Socket not connected

ENOTCONN

Connection closed

recvmsg()

  1. ssize_t recvmsg (int fd,struct msghdr * msg,int flags )

Description:

Receives data from a specified socket.

Parameters:

Name

Description

fdIndicates the socket descriptor.
msgIndicates the pointer to the address to receive the message header.
flagsIndicates the socket flags. This parameter has the following values:

value

Description

MSG_DONTWAIT

Enables the non-blocking operation.

MSG_MORE

The caller has more data to send.

MSG_NOSIGNAL

No signals are generated.

Attention:

This function does not allow sending ancillary data. Currently, the length of the array defined by msg_iov can only be 1.

Returns:

Returns the length of the received data if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

EDESTADDRREQ

Invalid connection

ENOMEM

Memory copy exception

EIO

Incorrect connection type obtained based on the socket descriptor

send()

  1. ssize_t send (int fd,constvoid* buf,size_t len,int flags )

Description:

Sends data to another socket.

Parameters:

Name

Description

fdIndicates the socket descriptor.
bufIndicates the pointer to a buffer for storing the data to be sent.
lenIndicates the length of the buffer pointed to by buf.
flagsIndicates the socket flags. This parameter has the following values:

value

Description

MSG_DONTWAIT

Enables the non-blocking operation.

MSG_MORE

The caller has more data to send.

MSG_NOSIGNAL

No signals are generated.

Returns:

Returns the length of the sent data if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

EDESTADDRREQ

Invalid connection

ENOMEM

Memory copy exception

EOPNOTSUPP

Unsupported message type

ENOTCONN

Socket not connected

EIO

Incorrect connection type obtained based on the socket descriptor

sendmsg()

  1. ssize_t sendmsg (int fd,conststruct msghdr * msg,int flags )

Description:

Sends data to another socket.

Parameters:

Name

Description

fdIndicates the socket descriptor.
msgIndicates the pointer to the address of the message header to be sent.
flagsIndicates the socket flags. This parameter has the following values:

value

Description

MSG_DONTWAIT

Enables the non-blocking operation.

MSG_MORE

The caller has more data to send.

MSG_NOSIGNAL

No signals are generated.

Attention:

This function does not support ancillary data.

Returns:

Returns the length of the sent data if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

EDESTADDRREQ

Invalid connection

ENOMEM

Memory copy exception

EIO

Incorrect connection type obtained based on the socket descriptor

EOPNOTSUPP

Unsupported message type

sendto()

  1. ssize_t sendto (int fd,constvoid* buf,size_t len,int flags,conststruct[sockaddr]($api-api-SmartVision-Devices-sockaddr.md)* addr,socklen_t alen )

Description:

Sends data to another socket.

Parameters:

Name

Description

fdIndicates the socket descriptor.
bufIndicates the pointer to a buffer for storing the data to be sent.
lenIndicates the length of the buffer pointed to by buf.
flagsIndicates the socket flags. This parameter has the following values:
addrIndicates the pointer to the destination network address.
alenIndicates the length of the destination network address.

value

Description

MSG_DONTWAIT

Enables the non-blocking operation.

MSG_MORE

The caller has more data to send.

MSG_NOSIGNAL

No signals are generated.

Returns:

Returns the length of the sent data if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

EBADF

Invalid socket or socket status exception

EDESTADDRREQ

Invalid connection

ENOMEM

Memory copy exception

EOPNOTSUPP

Unsupported message type

ENOTCONN

Socket not connected

EIO

Incorrect connection type obtained based on the socket descriptor

setprotoent()

  1. void setprotoent (int stayopen)

Description:

Opens a connection to the database and sets the next entry to the first entry.

Parameters:

Name

Description

stayopenReserved for interface compatibility (not used currently).

Attention:

The stayopen parameter does not take effect. It is equivalent to nonzero for getprotoent and zero for getprotobyname and getprotobynumbmer.

setsockopt()

  1. int setsockopt (int fd,int level,int optname,constvoid* optval,socklen_t optlen )

Description:

Sets the socket options.

Parameters:

Name

Description

fdIndicates the socket descriptor.
levelIndicates the protocol level at which the option resides. Only SOL_SOCKET is supported.
optnameIndicates the socket options to set, which has the following values:
optvalIndicates the pointer to the option data.
optlenIndicates the size of the buffer pointed to by optval.

value

Description

SO_BROADCAST

Permits sending broadcast messages.

SO_RCVTIMEO

Receiving data times out.

SO_RCVBUF

Sets or gets the maximum socket receiving buffer in bytes.

SO_DONTROUTE

Prohibits messages from being sent via a gateway.

SO_BINDTODEVICE

Binds this socket to a particular device.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Small optlen

EBADF

Invalid socket or socket status exception

EFAULT

The input parameter is a null pointer.

ENOBUFS

Retrieved length exception

ENOMEM

Memory copy exception

shutdown()

  1. int shutdown (int sockfd,int how )

Description:

Shuts down a socket.

Parameters:

Name

Description

sockfdIndicates the socket descriptor.
howIndicates how to shut down the socket. You can disable either receptions by SHUT_RD or transmissions by SHUT_WR, or both by SHUT_RDWR.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Invalid input parameter

ENOTCONN

Socket not connected

ENOMEM

Memory copy exception

EIO

Incorrect connection type obtained based on the socket descriptor

socket()

  1. int socket (int domain,int type,int protocol )

Description:

Creates a socket and returns its descriptor.

Parameters:

Name

Description

domainIndicates the socket domain.
typeIndicates the socket type.
protocolIndicates the socket protocol.

Attention:

Only the following socket domains are supported: AF_INET, AF_INET6. Only the socket types SOCK_RAW, SOCK_DGRAM and SOCK_STREAM are supported, and the OR operation between the extra socket flag and the socket type is not supported.

Returns:

Returns the descriptor for the new socket if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EAFNOSUPPORT

Invalid socket domain

ESOCKTNOSUPPORT

Unsupported socket domain

EPROTONOSUPPORT

Unsupported protocol

EINVAL

Invalid input parameter

ENOBUFS

Connection setup error

ENFILE

File table addition exception