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| #include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <time.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <string.h>
#define BUFFER_SIZE 1023
int setnonblocking( int fd )
{
int old_option = fcntl( fd, F_GETFL );
int new_option = old_option | O_NONBLOCK;
fcntl( fd, F_SETFL, new_option );
return old_option;
}
int unblock_connect( const char* ip, int port, int time )
{
int ret = 0;
struct sockaddr_in address;
bzero( &address, sizeof( address ) );
address.sin_family = AF_INET;
inet_pton( AF_INET, ip, &address.sin_addr );
address.sin_port = htons( port );
int sockfd = socket( PF_INET, SOCK_STREAM, 0 );
int fdopt = setnonblocking( sockfd );
ret = connect( sockfd, ( struct sockaddr* )&address, sizeof( address ) );
if ( ret == 0 )
{
printf( "connect with server immediately\n" );
fcntl( sockfd, F_SETFL, fdopt );
return sockfd;
}
else if ( errno != EINPROGRESS )
{
printf( "unblock connect not support\n" );
return -1;
}
fd_set readfds;
fd_set writefds;
struct timeval timeout;
FD_ZERO( &readfds );
FD_SET( sockfd, &writefds );
timeout.tv_sec = time;
timeout.tv_usec = 0;
ret = select( sockfd + 1, NULL, &writefds, NULL, &timeout );
if ( ret <= 0 )
{
printf( "connection time out\n" );
close( sockfd );
return -1;
}
if ( ! FD_ISSET( sockfd, &writefds ) )
{
printf( "no events on sockfd found\n" );
close( sockfd );
return -1;
}
int error = 0;
socklen_t length = sizeof( error );
if( getsockopt( sockfd, SOL_SOCKET, SO_ERROR, &error, &length ) < 0 )
{
printf( "get socket option failed\n" );
close( sockfd );
return -1;
}
if( error != 0 )
{
printf( "connection failed after select with the error: %d \n", error );
close( sockfd );
return -1;
}
printf( "connection ready after select with the socket: %d \n", sockfd );
fcntl( sockfd, F_SETFL, fdopt );
return sockfd;
}
int main( int argc, char* argv[] )
{
if( argc <= 2 )
{
printf( "usage: %s ip_address port_number\n", basename( argv[0] ) );
return 1;
}
const char* ip = argv[1];
int port = atoi( argv[2] );
int sockfd = unblock_connect( ip, port, 10 );
if ( sockfd < 0 )
{
return 1;
}
shutdown( sockfd, SHUT_WR );
sleep( 200 );
printf( "send data out\n" );
send( sockfd, "abc", 3, 0 );
return 0;
}
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