malloc（）用于struct成员 [英] malloc() for struct member
问题描述
您好，我有一个非常简单的问题，我现在对
感到有点困惑。可以通过malloc（）或calloc（）为
结构成员分配内存然后调用free（）吗？例如，我在下面有代码
。
struct mystruct {
int a;
char * b;
int c;
};
struct mystruct myobject;
myobject.b =（char *）malloc（50）;
....
....
免费（myobject.b）;
上面的代码是好的，还是有任何潜在的问题？
谢谢！
Hello, I have a very simple question that I''m a bit confused about
right now. Is it OK to allocate memory by malloc() or calloc() for a
struct member and then call free() on it? For example, I have the code
below.
struct mystruct {
int a;
char *b;
int c;
};
struct mystruct myobject;
myobject.b = (char *)malloc(50);
....
....
free(myobject.b);
Is the above code OK, or is there any potential problem with it?
Thanks!
推荐答案
" googler" < PI ******** @ yahoo.com>写道：
"googler" <pi********@yahoo.com> writes:
你好，我有一个非常简单的问题，我现在对
感到有些困惑。可以通过malloc（）或calloc（）为
struct成员分配内存然后调用free（）吗？例如，我的代码如下所示。
struct mystruct {
int a;
char * b;
int c;
结构mystruct myobject;
myobject.b =（char *）malloc（50）;
...
...
free（myobject.b）;
上面的代码是好的，还是有任何潜在的问题？
Hello, I have a very simple question that I''m a bit confused about
right now. Is it OK to allocate memory by malloc() or calloc() for a
struct member and then call free() on it? For example, I have the code
below.
struct mystruct {
int a;
char *b;
int c;
};
struct mystruct myobject;
myobject.b = (char *)malloc(50);
...
...
free(myobject.b);
Is the above code OK, or is there any potential problem with it?
我能看到的唯一问题就是你施放了malloc（）的结果。
这是合法但不必要的，可以掩盖错误。将行改为
到
myobject.b = malloc（50）;
除此之外，我没有看错。
-
Keith Thompson（The_Other_Keith） ks *** @ mib.org < http://www.ghoti.net/~kst>
圣地亚哥超级计算机中心< *> < http://users.sdsc.edu/~kst>
我们必须做点什么。这是事情。因此，我们必须这样做。
The only problem I can see is that you cast the result of malloc().
This is legal but unnecessary, and can mask errors. Change the line
to
myobject.b = malloc(50);
Other than that, I don''t see anything wrong.
--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.
2005年10月5日20:06:15 -0700，googler < PI ******** @ yahoo.com>写道：
On 5 Oct 2005 20:06:15 -0700, "googler" <pi********@yahoo.com> wrote:
你好，我有一个非常简单的问题，我现在对
有点困惑。可以通过malloc（）或calloc（）为
struct成员分配内存然后调用free（）吗？例如，我的代码如下所示。
struct mystruct {
int a;
char * b;
int c;
} mystruct myobject;
myobject.b =（char *）malloc（50）;
不要从malloc投出回报。它没有帮助，可能会导致
编译器抑制你真正想要的诊断....
...
free（myobject.b）;
这是你避免内存泄漏的方法。是什么促成了
的问题？
上面的代码是好的，还是有任何潜在的问题？
谢谢！
Hello, I have a very simple question that I''m a bit confused about
right now. Is it OK to allocate memory by malloc() or calloc() for a
struct member and then call free() on it? For example, I have the code
below.
struct mystruct {
int a;
char *b;
int c;
};
struct mystruct myobject;
myobject.b = (char *)malloc(50);
Don''t cast the return from malloc. It doesn''t help and may cause the
compiler to suppress a diagnostic you really want to see....
...
free(myobject.b);
This is how you would avoid a memory leak. What prompted the
question?
Is the above code OK, or is there any potential problem with it?
Thanks!
<<删除电子邮件的del>>
<<Remove the del for email>>
>是什么促成了这个问题？
像我给的那个代码导致了崩溃。这就是我发布
问题的原因。我的主要观点是，如果在结构成员上完成分配和释放内存是否正常（我知道它没关系，但上面的崩溃使我成为了一个
位我认为这是一个编译问题，因为发布版本有效，而且b $ b发生了调试版本的崩溃（这很奇怪，因为它是因为它是混乱的）。
通常
反过来说。
> What prompted the question?
A code like the one I gave resulted in a crash. That''s why I posted the
question. My main point was if allocating and freeing memory is OK when
done on a struct member (I knew it''s OK, but the above crash made me a
bit confused).
I presume it''s a compilation problem since the release build works and
the crash happens for debug build (which is weird since it is usually
the other way round).
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