[英]debugging segmentation fault using threads
When debugging my c program I get this error message 调试我的C程序时,出现此错误消息
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff77f6700 (LWP 14945)]
__strcpy_sse2_unaligned ()
at ../sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S:532
532 ../sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S: Aucun fichier ou dossier de ce type.
I think that it's "useless" to post my code because it doesn't precise the error line. 我认为发布我的代码是“无用的”,因为它无法精确显示错误行。
But I know I think it cames from this function: 但我知道我认为它来自此功能:
void add_user(tlistU *lu, user * u,tuser *new)
{
tuser *nouveau = malloc(sizeof(tuser));
u =malloc(sizeof(*u));
if (lu == NULL || nouveau == NULL)
{
exit(EXIT_FAILURE);
}
strcpy(nouveau->users->nickname,u->nickname);
nouveau->next=lu->first;
lu->first=nouveau;
}
( nickname is a 9 char string ) (昵称是一个9个字符的字符串)
Your code is a little strange. 您的代码有点奇怪。 The cause of the crash is probably this, however:
但是,崩溃的原因可能是:
strcpy(nouveau->users->nickname,u->nickname);
Note that nouveau
is a block of uninitialised memory that you just requested. 请注意,
nouveau
是您刚刚请求的未初始化内存的块。 You are then accessing nouveau->users->nickname
, which assumes that nouveau->users
is a valid pointer. 然后,您将访问
nouveau->users->nickname
,它假定nouveau->users
是有效的指针。
The other thing that's happening is overwriting u
here: 这是发生的另一件事是重写
u
在这里:
u = malloc(sizeof(*u));
I suspect that what you actually meant to do was something like this: 我怀疑您的实际意图是这样的:
nouveau->users = malloc(sizeof(*u));
That would solve both issues. 这将解决两个问题。
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