Linux network programming related functions

Network

struct SOCKADDR
{
sa_falimy_t sa_family; Protocol family
Char sa_data[14]; Protocol Family Data
};

struct SOCKADDR_IN
{
U8 Sin_len; Length of sockaddr_in, 16
U8 sin_family; Protocol family
U16 Sin_port; Port
struct IN_ADDR sin_add; IP address, 32-bit
Char Sin_zero[8]//unused
}

int socket (int family, int type, int protocol)
Parameters:
Family: Protocol family, Common Af_inet (IPV4)
Type: Socket type, common sock_stream (byte stream)
Protocol: Protocol type, typically 0 (TCP)
return value:
FD: Socket descriptor function Call succeeded: Non-negative integer failure: 1

int bind (int socked, const struct SOCKADDR *my_addr, socklen_t Addrlen)
Parameters:
SOCKFD: Socket Descriptor
my_addr:aockaddr pointer, IP and port included
addrlen:sizeof (struct sockaddr)
return value:
0: Success
-1: Failure

int listen (int socked, int backlog)
Parameters:
socked: Socket Descriptor
Backlog: The maximum number of connections queued
return value:
0: Success
-1: Failure

int accept (int socked, struct sockaddr *addr, socklen_t *addrlen)
Parameters:
socked: Socket Descriptor
Addr: Client sock information
Addrlen: Client sock structure length
return value:
FD: Socket descriptor for new client links

int connect (int socked, struct sockaddr *addr, int addrlen)
Parameters:
socked: Socket Descriptor
Addr:sock Information
Addrlen:sock length
return value:
0: Success
-1: Failure

int write (int socked, char* data, int size)
Parameters:
socked: Socket Descriptor
Data:
Size: Data length
return value:
Size: Successful write length

int read (int socked, char* data, int size)
Parameters:
socked: Socket Descriptor
Data:
Size: Maximum data length
return value:
Size: Read length successfully

int select (int Nfds, fd_set* Readfds, fd_set* Writefds, fd_set* exceptfds, struct timeval* timeout)
Parameters:
NFDS: Maximum socket descriptor +1
Readfds: A collection of socket descriptors that need to monitor data read operations
Writefds: A collection of socket descriptors that need to monitor data write operations
Exceptfds: A collection of socket descriptors that need to be monitored for exceptions to occur
Timeout: Set maximum wait time
return value:
-1: Error occurred
0: Timeout
positive integers: Monitored for the selected watch content
Tool functions:
Fd_zero (): Cleanup Descriptor Collection
Fd_set (): Add a new descriptor to the collection
FD_CLR (): Remove a descriptor from the collection
Fd_isset (): Determines whether a descriptor is in the collection

int poll (struct polled* FDS, nfds_t nfds, int timeout)
Parameters:
FDS: Socket descriptor, listener event collection, event collection actually occurring
Nfds: ...
Timeout: Longest wait event

int epoll_create (int size);
Parameters:
Size: Maximum number of listeners
return value:
Epfd:epoll Descriptor
int epoll_ctl (int epfd, int op, int fd, struct epoll_event *event);
Role:
Registering events
Parameters:
Epfd:epoll Descriptor
OP: Operation type (add, modify, delete)
FD: Socket Descriptor
Event: Specific Events
int epoll_wait (int epfd, struct epoll_event * events, int maxevents, int timeout);
Parameters:
EPFD:p Oll Descriptor
Events: Event collection that occurs
Maxevents: Maximum number of events
Timeout: Maximum wait event

Linux network programming related functions