objective-C NSThread能否访问全局变量?
好的,基本上我的应用程序中每隔一两秒钟就有一个运行循环,同时我还有另一个线程在通过objective-C NSThread能否访问全局变量?,objective-c,cocoa,multithreading,global-variables,Objective C,Cocoa,Multithreading,Global Variables,好的,基本上我的应用程序中每隔一两秒钟就有一个运行循环,同时我还有另一个线程在通过listenForPackets方法循环广播消息仅在发生其他操作方法时启动。这个问题的重要部分是,当侦听器线程与主线程分开运行时,它从不打印任何打印命令,并且似乎不允许访问我定义的名为recvMessage的全局变量,该变量位于接口和实现部分之外 在我的代码中,我对它进行了设置,以便每次它通过主运行循环运行时,它都会更新GUI中的UILabel。当应用程序运行时,我的标签始终保持空白,从不更改。我已经仔细检查了GU
listenForPackets
方法循环<代码>广播消息仅在发生其他操作方法时启动。这个问题的重要部分是,当侦听器线程与主线程分开运行时,它从不打印任何打印命令,并且似乎不允许访问我定义的名为recvMessage
的全局变量,该变量位于接口和实现部分之外
在我的代码中,我对它进行了设置,以便每次它通过主运行循环运行时,它都会更新GUI中的UILabel。当应用程序运行时,我的标签始终保持空白,从不更改。我已经仔细检查了GUI,所有的东西都正确地链接在那里,我的标签也被正确地实例化了(我在下面的代码中使用名称“label”作为UILabel的实例)。有人知道为什么我的标签在更新吗?我相信人际关系方面的事情很好,因为我刚刚完成了,一切都在“交谈”中。也许这是一个我不知道的变量范围问题,或者允许单独的线程访问全局变量,比如我在下面使用的(rcvMessage)?我对多线程应用程序相当陌生,但我不认为使用NSThread(只有一行代码)实现它真的有那么难
全局变量
NSString *recvMessage;
主运行循环-每次通过运行循环时更新标签的部分
if (label.text != recvMessage)
label.text = recvMessage
说话人法
-(void)broadcastMessage { // (NSString*)msg {
msg = @"From_Master";
NSLog(@"broadcastMessage - Stage 1");
mc_ttl = 15; // number of node hops the message is allowed to travel across the network
// define the port we will be using
mc_port = MYPORT;
// create a socket for sending to the multicast address
if ((sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
NSLog(@"ERROR: broadcastMessage - socket() failed");
return;
}
memset(&mc_addr, 0, sizeof(mc_addr));
mc_addr.sin_family = AF_INET;
mc_addr.sin_addr.s_addr = inet_addr(GROUP_ADDRESS);
mc_addr.sin_port = htons(MYPORT);
NSLog(@"broadcastMessage - Stage 2");
// set the TTL (time to live/hop count) for the send
if ((setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL, &mc_ttl, sizeof(mc_ttl))) < 0) {
NSLog(@"ERROR: broadcastMessage - setsockopt() failed");
return;
}
NSLog(@"broadcastMessage - Stage 3");
// clear send buffer
memset(send_str, 0, sizeof(send_str));
// convert the message to a C string to send
[msg getCString:send_str maxLength:MAX_LEN encoding:NSASCIIStringEncoding];
//while (fgets(send_str, MAX_LEN, stdin)) {
NSLog(@"broadcastMessage - Stage 4");
NSLog(@"Message =");
printf(send_str);
// send string to multicast address
if ((sendto(sock, send_str, sizeof(send_str), 0, (struct sockaddr *)&mc_addr, sizeof(mc_addr))) < 0) {
NSLog(@"ERROR: broadcastMessage - sendto() sent incorrect number of bytes");
//return;
}
NSLog(@"Sent Message -");
printf(send_str);
NSLog(@"broadcastMessage - Stage 5");
// clear send buffer
memset(send_str, 0, sizeof(send_str));
NSLog(@"broadcastMessage - Stage 6 - Complete");
close(sock);
}
-(void)广播消息{//(NSString*)消息{
msg=@“来自主机”;
NSLog(“广播信息-第1阶段”);
mc_ttl=15;//允许消息在网络上传输的节点跳数
//定义我们将使用的端口
mc_port=MYPORT;
//创建用于发送到多播地址的套接字
如果((sock=socket(AF_INET,sock_DGRAM,IPPROTO_UDP))<0){
NSLog(@“错误:广播消息-套接字()失败”);
返回;
}
memset(&mc_addr,0,sizeof(mc_addr));
mc_addr.sin_family=AF_INET;
mc_addr.sin_addr.s_addr=inet_addr(组地址);
mc_addr.sin_port=htons(MYPORT);
NSLog(“广播信息-第2阶段”);
//设置发送的TTL(生存时间/跳数)
if((setsockopt(sock,IPPROTO_IP,IP_MULTICAST_TTL,&mc_TTL,sizeof(mc_TTL))小于0){
NSLog(@“错误:broadcastMessage-setsockopt()失败”);
返回;
}
NSLog(“广播信息-第3阶段”);
//清除发送缓冲区
memset(send_str,0,sizeof(send_str));
//将消息转换为要发送的C字符串
[msg getCString:send_str maxLength:MAX_leng encoding:NSASCIIStringEncoding];
//while(fgets(send_str,MAX_LEN,stdin)){
NSLog(“广播信息-第4阶段”);
NSLog(@“Message=”);
printf(send_str);
//发送字符串到多播地址
如果((发送到(sock,send_str,sizeof(send_str),0,(struct sockaddr*)和mc_addr,sizeof(mc_addr)))<0){
NSLog(@“错误:broadcastMessage-sendto()发送的字节数不正确”);
//返回;
}
NSLog(@“已发送消息-”);
printf(send_str);
NSLog(“广播信息-第5阶段”);
//清除发送缓冲区
memset(send_str,0,sizeof(send_str));
NSLog(@“广播消息-第6阶段-完成”);
关闭(袜子);
}
侦听器方法
-(void)listenForPackets {
listeningFlag_on = 1; // allows reuse of the same socket
NSLog(@"listenForPackets - Stage 1");
if ((listeningSock = socket(AF_INET, SOCK_DGRAM,IPPROTO_UDP)) < 0) {
NSLog(@"ERROR: listenForPackets - socket() failed");
return;
// make the method return an int instead of void and use this statement to check for errors
}
NSLog(@"listenForPackets - Stage 2");
// set reuse port to on to allow multiple binds per host
if ((setsockopt(listeningSock, SOL_SOCKET, SO_REUSEADDR, &listeningFlag_on, sizeof(listeningFlag_on))) < 0) {
NSLog(@"ERROR: listenForPackets - setsockopt() Reuse failed");
return;
// make the method return an int instead of void and use this statement to check for errors
}
// construct a multicast address structure after erasing anything in the listeningmc_addr structure
memset(&listeningmc_addr, 0, sizeof(listeningmc_addr));
listeningmc_addr.sin_family = AF_INET;
listeningmc_addr.sin_addr.s_addr = htonl(INADDR_ANY); // different from sender
listeningmc_addr.sin_port = htons(MYPORT);
// bind multicast address to socket
if ((bind(listeningSock, (struct sockaddr *)&listeningmc_addr, sizeof(listeningmc_addr))) < 0) {
NSLog(@"ERROR: listenForPackets - bind() failed");
perror("Bind() -");
return; // make the method return an int instead of void and use this statement to check for errors
}
//*********************************************************************************
NSString *ipAddress = [[NSString alloc] initWithString:self.getIPAddress];
const char *tmp = [ipAddress UTF8String];
listeningMc_addr_str = tmp;
printf("%s\n", listeningMc_addr_str);
listeningMc_req.imr_multiaddr.s_addr = inet_addr(GROUP_ADDRESS);
listeningMc_req.imr_interface.s_addr = htonl(INADDR_ANY);
// send an ADD MEMBERSHIP message via setsockopt
if ((setsockopt(listeningSock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &listeningMc_req, sizeof(listeningMc_req))) < 0) {
NSLog(@"ERROR: listenForPackets - setsockopt() failed");
int err = errno;
NSLog(@"errno - %i", err);
NSLog(@"Error = %s", strerror(err));
perror("ERROR");
return; // make the method return an int instead of void and use this statement to check for errors
}
NSLog(@"listenForPackets - Stage 3");
for (;;) { // loop forever
// clear the receive buffers & structs
memset(listeningRecv_str, 0, sizeof(listeningRecv_str));
listeningFrom_len = sizeof(listeningFrom_addr);
memset(&listeningFrom_addr, 0, listeningFrom_len);
NSLog(@"Test #1 Complete");
//msgStatus.text = @"Waiting...";
// block waiting to receive a packet
listeningFrom_len = sizeof(listeningmc_addr);
if ((listeningRecv_len = recvfrom(listeningSock, listeningRecv_str, MAX_LEN, 0, (struct sockaddr*)&listeningmc_addr, &listeningFrom_len)) < 0) {
NSLog(@"ERROR: listenForPackets - recvfrom() failed");
return; // make the method return an int instead of void and use this statement to check for errors
}
NSLog(@"Test #2 Complete - Received a Message =");
NSLog(@"listenForPackets - Stage 4");
// listeningRecv_str
**tmpString = [[NSString alloc] initWithCString:listeningRecv_str encoding:NSASCIIStringEncoding];
NSLog(@"Message Received =");
NSLog(tmpString);
recvMessage = tmpString;**
//}
// received string
printf("Received %d bytes from %s: ", listeningRecv_len, inet_ntoa(listeningFrom_addr.sin_addr));
printf("%s", listeningRecv_str);
//}
}
// send a DROP MEMBERSHIP message via setsockopt
if ((setsockopt(listeningSock, IPPROTO_IP, IP_DROP_MEMBERSHIP, (void*) &listeningMc_req, sizeof(listeningMc_req))) < 0) {
NSLog(@"ERROR: listenForPackets - setsockopt() drop membership failed");
//return 1; // make the method return an int instead of void and use this statement to check for errors
}
close(listeningSock);
NSLog(@"listenForPackets - Stage 5 - Complete");
}
-(void)listenForPackets{
ListingFlag_on=1;//允许重用同一套接字
NSLog(“listenForPackets-Stage 1”);
如果((listingsock=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP))<0){
NSLog(@“错误:listenForPackets-socket()失败”);
返回;
//使方法返回int而不是void,并使用此语句检查错误
}
NSLog(“listenForPackets-Stage 2”);
//将重用端口设置为on以允许每个主机进行多个绑定
if((setsockopt(listingsock,SOL_SOCKET,SO_REUSEADDR,&listingflag_on,sizeof(listingflag_on))小于0){
NSLog(@“错误:listenForPackets-setsockopt()重用失败”);
返回;
//使方法返回int而不是void,并使用此语句检查错误
}
//在删除ListingMC_addr结构中的任何内容后构造多播地址结构
memset(&listingmc_addr,0,sizeof(listingmc_addr));
ListingMC\u addr.sin\u family=AF\u INET;
listeningmc_addr.sin_addr.s_addr=htonl(INADDR_ANY);//与发件人不同
listeningmc_addr.sin_port=htons(MYPORT);
//将多播地址绑定到套接字
if((bind(listeningSock,(struct sockaddr*)和listeningmc_addr,sizeof(listeningmc_addr)))<0){
NSLog(@“错误:listenForPackets-bind()失败”);
perror(“Bind()-”);
return;//使方法返回int而不是void,并使用此语句检查错误
}
//*********************************************************************************
NSString*ipAddress=[[NSString alloc]initWithString:self.getIPAddress];
常量字符*tmp=[ipAddress UTF8String];
listeningMc_addr_str=tmp;
printf(“%s\n”,listingmc\u addr\u str);
ListingMC_req.imr_multiaddr.s_addr=inet_addr(组地址);
listeningMc_req.imr_interface.s_addr=htonl(INADDR_ANY);
//通过setsockopt发送添加会员信息
if((setsockopt(listingsock、IPPROTO_IP、IP_添加_成员资格和listingmc_请求、sizeof(listingmc_请求))小于0){
NSLog(@“错误:listenForPackets-setsockopt()失败”);
int err=errno;
NSLog(@“errno-%i”,err);
NSLog(@“Error=%s”,strerror(err));
佩罗(“错误”);
return;//使方法返回int而不是void,并使用此语句检查错误
}
NSLog(“listenForPackets-Stage 3”);
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