In linux, is network programming non-blocking? Is the server unable to accept data?

In linux, is network programming non-blocking? Is the server unable to accept data? -- Linux general technology-Linux technology and application information. For details, refer to the following section. /* This is the client code */
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Deprecision S_PORT 3333
# Define BUFFER 100.

Int main (int argc, char ** argv)
{
Struct sockaddr_in server_addr;
Int c_fd, s_fd;
Socklen_t s_len;
Char * buffer = (char *) malloc (BUFFER + 1 );
Char addr_t [BUFFER];
Int s_bits, r_bits =-1;
If (argc! = 2 ){
Printf ("usage: no valid argument! \ N "); exit (-1 );
}
If (! Buffer) {perror ("malloc"); exit (-1 );}
Bzero (buffer, BUFFER + 1 );
C_fd = socket (AF_INET, SOCK_STREAM, 0 );
If (! C_fd) {perror ("socket"); exit (-1 );}
Server_addr.sin_port = htons (S_PORT );
/* Inet_ton (AF_INET, argv [1], addr_t );*/
Server_addr.sin_addr.s_addr = inet_addr (argv [1]);
Server_addr.sin_family = AF_INET;
S_len = sizeof (struct sockaddr_in );
If (s_fd = connect (c_fd, (struct sockaddr *) & server_addr, s_len) =-1 ){
Perror ("connect"); exit (-1 );
}
Gets (buffer );
S_bits = send (c_fd, buffer, sizeof (buffer), 0 );
If (s_bits = sizeof (buffer )){
Printf ("success send to server: % s", buffer );
}
Else {
Printf ("fail send to server! \ N ");
}
R_bits = recv (c_fd, buffer, sizeof (buffer), 0 );
If (r_bits =-1 ){
Printf ("receive from server error! \ N "); exit (-1 );
}
Else printf ("receive from the server: % s \ n", buffer );
If (close (c_fd) =-1 ){
Printf ("close the socket error! \ N "); exit (-1 );
}
Return 1;
}
/* This is the server code */


# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Deprecision S_PORT 3333
# Define BUFFER 100.
Void up_chars (char * buf ){
Int I = 0;
While (buf = Toupper (buf))! = '\ 0') I ++;
}

Int
Main (void)
{
Struct sockaddr_in server_addr;
Struct sockaddr_in client_addr;
Int s_fd;
Int c_fd;
Socklen_t s_len;
Char * buffer;
Char addr_t [BUFFER];
Int temp;
Int flags;
If (buffer = (char *) malloc (BUFFER + 1) = NULL ){
Fprintf (stderr, "% s", strerror (errno); exit (-1 );
}
If (s_fd = socket (AF_INET, SOCK_STREAM, 0) =-1 ){
Perror ("socket"); exit (-1 );
}
Flags = fcntl (s_fd, F_GETFL );
Fcntl (s_fd, F_SETFL, flags | O_NONBLOCK );
S_len = sizeof (struct sockaddr_in );
Memset (& server_addr, '\ 0', s_len );
Server_addr.sin_port = htons (S_PORT );
Server_addr.sin_addr.s_addr = INADDR_ANY;
Server_addr.sin_family = AF_INET;
If (bind (s_fd, (struct sockaddr *) & server_addr, s_len) =-1 ){
Printf ("% s", strerror (errno); exit (-1 );
}
If (listen (s_fd, 10) =-1 ){
Printf ("% s", strerror (errno); exit (-1 );
}
While (1 ){
Int bits;
/* Sleep (1 );*/
C_fd = accept (s_fd, (struct sockaddr *) & client_addr, (socklen_t *) & s_len );
If (c_fd =-1 ){
Continue;
}
Else {
Inet_ntop (AF_INET, & client_addr.sin_addr, addr_t, sizeof (addr_t ));
Printf ("client ip is % s, port is % d \ n", addr_t, ntohs (client_addr.sin_port ));
}
Bits = recv (c_fd, buffer, sizeof (buffer), 0 );
If (bits =-1 & errno! = EAGAIN ){
Printf ("fail to receive from client \ n"); continue;
}
Else if (errno = EAGAIN ){
Printf ("socket is not ready now \ n"); continue;
}
Printf ("content is: % s \ n", buffer );
Up_chars (buffer );
Bits = send (c_fd, buffer, sizeof (buffer), 0 );
If (bits =-1 & errno! = EAGAIN ){
Printf ("fail to write \ n"); exit (-1 );
}
Else if (errno = EAGAIN ){
Printf ("socket is not ready! \ N "); continue;
}
}
If (close (s_fd) =-1 ){
Printf ("fail to close \ n"); exit (-1 );
}
Return 1;
}