socket() 返回 -1 但 errno 0

发布于 2024-12-13 04:33:05 字数 820 浏览 8 评论 0原文

我尝试在 mingw 上创建 UDP 套接字，但 socket() 返回 -1，errno = 0。奇怪的。我已经包含了winsock2.h。最初我在设置后遇到编译错误未定义的对socket@12的引用 将-lws2_32和-lwsock32添加到Code::Block的Linker Settings中，编译成功。

sockfd = socket(AF_INET, SOCK_DGRAM, 0);
RDF_LOG(kDEBUG, "sockfd %d ", sockfd);
if (sockfd < 0){
    RDF_LOG(kERROR, "ERROR: %s , errno %d\n", strerror(errno), errno);
}

结果--> 套接字FD-1 错误：没有错误，errno 0

好的，我将 RDF_LOG 更改为 fprintf。

int tmp = 0;

sockfd = socket(AF_INET, SOCK_DGRAM, 0);
tmp = errno;
fprintf(stderr, "sockfd %d ", sockfd);
if (sockfd < 0){
    fprintf(stderr, "socket: %s , errno %d\n", strerror(tmp), tmp);
}

返回的结果仍然是 --> sockfd -1 套接字：无错误，errno 0 难道mingw不支持errno吗？

原文

I tried to create a UDP socket on mingw, but socket() returns -1, with errno = 0. Strange.
I have included winsock2.h.
Initially I had compilation error undefined reference to socket@12, after setting
-lws2_32 and -lwsock32 to Linker Settings of Code::Block, compilation success.

sockfd = socket(AF_INET, SOCK_DGRAM, 0);
RDF_LOG(kDEBUG, "sockfd %d ", sockfd);
if (sockfd < 0){
    RDF_LOG(kERROR, "ERROR: %s , errno %d\n", strerror(errno), errno);
}

Result -->
sockfd -1
ERROR: No error , errno 0

OK, I change RDF_LOG to fprintf instead.

int tmp = 0;

sockfd = socket(AF_INET, SOCK_DGRAM, 0);
tmp = errno;
fprintf(stderr, "sockfd %d ", sockfd);
if (sockfd < 0){
    fprintf(stderr, "socket: %s , errno %d\n", strerror(tmp), tmp);
}

The result returned is, still, --> sockfd -1 socket: No error , errno 0
Is it possible that mingw does not support errno??

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

从﹋此江山别 2024-12-20 04:33:05

我要做的第一件事是：

sockfd = socket(AF_INET, SOCK_DGRAM, 0);
int tmp = errno;
RDF_LOG(kDEBUG, "sockfd %d ", sockfd);
if (sockfd < 0){
    RDF_LOG(kERROR, "ERROR: %s , errno %d\n", strerror(tmp), tmp);
}

我不知道RDF_LOG可能会对errno变量做什么，这会告诉你它是否改变或不改变。

另一件需要注意的事情是您是否已成功执行 WSAStartup。以下最小程序有望向您展示如何执行此操作，并提供调试的起点：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <winsock2.h>

int main (void) {
    WSADATA wsaData;
    int listenFd;

    if (WSAStartup(MAKEWORD(1,1), &wsaData) == SOCKET_ERROR) {
        printf ("Error initialising WSA.\n");
        return -1;
    }

    listenFd = socket (AF_INET, SOCK_STREAM, 0);
    if (listenFd  < 0) {
        printf ("Error %d opening socket.\n", errno);
        return -1;
    }

    return 0;
}

The first thing I would do is this:

sockfd = socket(AF_INET, SOCK_DGRAM, 0);
int tmp = errno;
RDF_LOG(kDEBUG, "sockfd %d ", sockfd);
if (sockfd < 0){
    RDF_LOG(kERROR, "ERROR: %s , errno %d\n", strerror(tmp), tmp);
}

I have no idea what RDF_LOG may be doing to the errno variable and this will tell you whether it changes it or not.

Another thing to look for is that you have successfully performed your WSAStartup. The following minimal program should hopefully show you how to do this, and provide a starting point for debugging:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <winsock2.h>

int main (void) {
    WSADATA wsaData;
    int listenFd;

    if (WSAStartup(MAKEWORD(1,1), &wsaData) == SOCKET_ERROR) {
        printf ("Error initialising WSA.\n");
        return -1;
    }

    listenFd = socket (AF_INET, SOCK_STREAM, 0);
    if (listenFd  < 0) {
        printf ("Error %d opening socket.\n", errno);
        return -1;
    }

    return 0;
}

回复收藏 0 原文