[英]Linux c++ recvfrom() changes (destroys) the [socket] file descriptor
I have written a simple UDP server. 我已经编写了一个简单的UDP服务器。 Well, naturally I use
recvfrom()
function somewhere in it. 好吧,我自然会在其中的某个地方使用
recvfrom()
函数。 I have searched the net for it, and found that it is caused by the buffer overflow. 我在网上搜索了它,发现它是由缓冲区溢出引起的。 Is this true?
这是真的? But I can't figure why my code fails and throws the same error, here is the part associated with
recvfrom()
: 但是我不知道为什么我的代码会失败并引发相同的错误,这是与
recvfrom()
相关的部分:
char messageFromClient[1024] = {0};
returnStatus = recvfrom(udpSocket, &messageFromClient, strlen(messageFromClient), 0, (struct sockaddr*)&udpSocket,
&addrlen);
The file descriptor before invocation of recvfrom()
is 3
but when I call it, it changes to -187301886
调用
recvfrom()
之前的文件描述符为3
但是当我调用它时,它变为-187301886
Your code fails because you specify 0 receive buffer size and you pass the socket file descriptor as the peer address argument (which overwrites its value): 您的代码失败,因为您指定了0的接收缓冲区大小,并且将套接字文件描述符作为对等地址参数传递(覆盖了它的值):
Fix: 固定:
char messageFromClient[1024];
sockaddr_in addr;
socklen_t addrlen = sizeof addr;
ssize_t received = recvfrom(udpSocket, messageFromClient, sizeof messageFromClient, 0, (sockaddr*)&addr, &addrlen);
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