homework-jianmu/2.0/deps/MQTT-C/examples/templates/posix_sockets.h

59 lines
1.4 KiB
C

#ifndef __POSIX_SOCKET_TEMPLATE_H__
#define __POSIX_SOCKET_TEMPLATE_H__
#include <stdio.h>
#include <sys/types.h>
#if !defined(WIN32)
#include <sys/socket.h>
#include <netdb.h>
#endif
#include <fcntl.h>
/*
A template for opening a non-blocking POSIX socket.
*/
int open_nb_socket(const char* addr, const char* port) {
struct addrinfo hints = {0};
hints.ai_family = AF_UNSPEC; /* IPv4 or IPv6 */
hints.ai_socktype = SOCK_STREAM; /* Must be TCP */
int sockfd = -1;
int rv;
struct addrinfo *p, *servinfo;
/* get address information */
rv = getaddrinfo(addr, port, &hints, &servinfo);
if(rv != 0) {
fprintf(stderr, "Failed to open socket (getaddrinfo): %s\n", gai_strerror(rv));
return -1;
}
/* open the first possible socket */
for(p = servinfo; p != NULL; p = p->ai_next) {
sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
if (sockfd == -1) continue;
/* connect to server */
rv = connect(sockfd, servinfo->ai_addr, servinfo->ai_addrlen);
if(rv == -1) continue;
break;
}
/* free servinfo */
freeaddrinfo(servinfo);
/* make non-blocking */
#if !defined(WIN32)
if (sockfd != -1) fcntl(sockfd, F_SETFL, fcntl(sockfd, F_GETFL) | O_NONBLOCK);
#else
if (sockfd != INVALID_SOCKET) {
int iMode = 1;
ioctlsocket(sockfd, FIONBIO, &iMode);
}
#endif
/* return the new socket fd */
return sockfd;
}
#endif