unsigned char* readFromIn() {
    unsigned char* text = malloc(1024);
    if (fgets(text,1024,stdin) != NULL) {          <--This is what's causing segmentation fault
        int textLen = strlen(text);
        if (textLen > 0 && text[textLen - 1] == '\n')
            text[textLen - 1] = '\0';     // getting rid of newline character
        return text;
    }
    else {
        free(text);
        return NULL;
    }
}

问题是,这个函数不会在任何地方被调用,只是为了确认,我将函数的名称更改为像9rawiohawr90awrhiokawrioawr这样的东西,并将printf语句放在函数的顶部.

我真的不确定为什么未调用的函数可能会导致分段错误错误.

我在ubuntu上使用gcc 4.6.3.

编辑：我知道那条线

if (fgets(text,stdin) != NULL) {

是有问题的代码,因为只要我注释掉条件,就不会发生分段错误.

我知道函数没有被调用,因为我没有看到我输出的printf调试语句的输出.

Edit2：我尝试将类型从unsigned char更改为char.仍然分段错误.我会尝试获取gdb输出.

Edit3：gdb backtrace产生了以下内容

#0 0xb7fa5ac2 in _IO_2_1_stdin_ () from /lib/i386-linux-gnu/libc.so.6
#1 0xb7faf2fb in libwebsocket_create_context (info=0xbffff280) at libwebsockets.c:2125
#2 0x0804a5bb in main()

做框架0,1,2特别没有输出任何有趣的东西.

编辑4：我已经尝试了评论中的所有建议,但无济于事,我仍然得到相同的分段错误.

所以我在虚拟操作系统上安装了一个新的Ubuntu副本并​​重新编译了我的代码.仍然出现同样的问题.
在我看来,问题在于我的代码或库本身是否存在一些模糊不清.我创建了一个演示问题的最小例子：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libwebsockets.h>


unsigned char* readFromIn() {
    unsigned char* text = malloc(1024);
    if (fgets(text,stdin) != NULL) { <--SEGMENTATION FAULT HERE
        int textLen = strlen(text);
        if (textLen > 0 && text[textLen - 1] == '\n')
            text[textLen - 1] = '\0';    
        return text;
    }
    else {
        free(text);
        return NULL;
    }
}

int callback_http(struct libwebsocket_context *context,struct libwebsocket *wsi,enum libwebsocket_callback_reasons reason,void *user,void *in,size_t len)
{
    return 0;
}

static struct libwebsocket_protocols protocols[] = {
    /* first protocol must always be HTTP handler */
    {
        "http-only",// name
        callback_http,// callback
        0              // per_session_data_size
    }
};

int main(void) {
    printf("Initializing Web Server\n");
        // server url will be http://localhost:8081
    int port = 8081;
    const char *interface = NULL;
    struct libwebsocket_context *context;
    // we're not using ssl
    const char *cert_path = NULL;
    const char *key_path = NULL;
    // no special options
    int opts = 0;


    struct lws_context_creation_info info;

    memset(&info,sizeof info);
    info.port = port;
    info.iface = interface;
    info.protocols = protocols;
    info.extensions = libwebsocket_get_internal_extensions();
    info.ssl_cert_filepath = NULL;
    info.ssl_private_key_filepath = NULL;
    info.gid = -1;
    info.uid = -1;
    info.options = opts;

    context = libwebsocket_create_context(&info);
    if (context == NULL) {
        fprintf(stderr,"libwebsocket init Failed\n");
        return 0;
    }

    printf("starting server...\n");

    while (1) {
        libwebsocket_service(context,50);
    }
    printf("Shutting server down...\n");
    libwebsocket_context_destroy(context);

    return 0;
}

这是我编译代码的方式

gcc -g testbug.c -o test -lwebsockets

这是我正在使用的库

http://git.libwebsockets.org/cgi-bin/cgit/libwebsockets/tag/?id=v1.23-chrome32-firefox24

您将看到我没有调用函数readFromIn(),一旦您尝试运行可执行文件就会发生分段错误.

我重新运行gdb,这次,回溯和帧告诉我更多的信息.

(gdb) run
Starting program: /home/l46kok/Desktop/websocketserver/test 
Initializing Web Server
[1384002761:2270] NOTICE: Initial logging level 7
[1384002761:2270] NOTICE: Library version: 1.3 unknown-build-hash
[1384002761:2271] NOTICE:  Started with daemon pid 0
[1384002761:2271] NOTICE:  static allocation: 4448 + (12 x 1024 fds) = 16736 bytes
[1384002761:2271] NOTICE:  canonical_hostname = ubuntu
[1384002761:2271] NOTICE:  Compiled with OpenSSL support
[1384002761:2271] NOTICE:  Using non-SSL mode
[1384002761:2271] NOTICE:  per-conn mem: 124 + 1360 headers + protocol rx buf
[1384002761:2294] NOTICE:  Listening on port 8081

Program received signal SIGSEGV,Segmentation fault.
0xb7fb1ac0 in _IO_2_1_stdin_ () from /lib/i386-linux-gnu/libc.so.6
(gdb) backtrace
#0  0xb7fb1ac0 in _IO_2_1_stdin_ () from /lib/i386-linux-gnu/libc.so.6
#1  0xb7fcc2c6 in libwebsocket_create_context () from /usr/local/lib/libwebsockets.so.4.0.0
#2  0x080488c4 in main () at testbug.c:483
(gdb) frame 1
#1  0xb7fcc2c6 in libwebsocket_create_context () from /usr/local/lib/libwebsockets.so.4.0.0
(gdb) frame 2
#2  0x080488c4 in main () at testbug.c:483
483         context = libwebsocket_create_context(&info);

所以是啊..我想我已经提供了所有信息……但我真的不确定问题是什么.该程序在第483行导致分段错误,但当我注释掉未被调用的有问题的函数时问题就消失了.