为什么VS2013抱怨“使用未初始化的内存"? [英] Why is VS2013 complaining about "using uninitialized memory"?
问题描述
我有这样的代码:
#include <stdio.h>
#include <stdlib.h>
typedef struct {
char *a;
char *b;
int c;
} my_type;
void free_my_type(my_type *p) {
if (p) {
if (p->a) free(p->a); // line 12
if (p->b) free(p->b); // line 13
free(p);
}
}
int main(void) {
my_type *p = malloc(sizeof(*p));
p->a = malloc(10);
p->b = malloc(10);
p->c = 10;
free_my_type(p);
return 0;
}
VS的代码分析抱怨我是:
VS's Code Analysis is complaining that I am:
"C6001 Using uninitialized memory '*p'"
'*p' is not initialized 12
Skip this branch, (assume 'p->b' is false) 13
'*p' is used, but may not have been initialized 13
我的意思是,它是一个指针,我正在检查它是否为NULL
.我怎么知道* p是否已初始化?
I mean, it's a pointer and I'm checking to see if it is NULL
. How will I ever know if *p is initialized?
奇怪的是,如果结构中只有1个其他指针(例如,只有char *a
),则不会触发警告.如果我在free(p->a)
之前执行free(p->b)
(交换第12和13行),也不会显示.
Oddly enough, if there's only 1 other pointer inside the struct -- only char *a
, for example -- the warning doesn't trigger. It also doesn't show up if I do free(p->b)
before free(p->a)
(swap lines 12 and 13).
推荐答案
Visual Studio 2013的分析器工具似乎有问题
It seems to be a problem with the analyzer tool of visual studio 2013
如此处所述:
https://randomascii.wordpress.com/2011/07/25/analyze-for-visual-studiothe-ugly-part-1/
https://randomascii.wordpress.com/2011/07/29/analyze-for-visual-studiothe-ugly-part-2/
https: //randomascii.wordpress.com/2011/09/13/analyze-for-visual-studio-the-ugly-part-5/
作为第5部分的更新,我们可以阅读以下内容:
as an update in the part 5, we can read this:
更新:幸运的是VC ++ 2013解决了许多此类问题,但__analysis_assume的问题仍然存在.
因此,即使他们使用最新的Visual Studio版本解决了许多此类警告问题,分析器工具仍会出现一些错误.
So even if they solved many of theses warning issues with newest visual studio versions, still some bugs occurs in the analyzer tool.
使用VS2015 Enterprise进行测试:出现相同的问题
Test with VS2015 Enterprise: gives the same problem
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