CERT C:Rule WIN30-C

Properly pair allocation and deallocation functions

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描述

规则定义

Properly pair allocation and deallocation functions.¹

Polyspace 实现

规则检查项会检查是否 Windows 上的分配/释放函数不匹配。

示例

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Windows 上的分配/取消分配函数不匹配

问题

当您使用的 Windows^® 释放函数未与相应的分配函数正确配对时，会出现 Windows 上的分配/释放函数不匹配。

风险

使用与分配函数不匹配的函数取消内存分配可能会导致内存损坏或未定义的行为。如果您使用的是旧版本的 Windows，不正确的函数还可能导致与新版本的兼容性问题。

修复

根据此表中列出的函数正确配对您的分配和释放函数。

分配函数	释放函数
`malloc()`	`free()`
`realloc()`	`free()`
`calloc()`	`free()`
`_aligned_malloc()`	`_aligned_free()`
`_aligned_offset_malloc()`	`_aligned_free()`
`_aligned_realloc()`	`_aligned_free()`
`_aligned_offset_realloc()`	`_aligned_free()`
`_aligned_recalloc()`	`_aligned_free()`
`_aligned_offset_recalloc()`	`_aligned_free()`
`_malloca()`	`_freea()`
`LocalAlloc()`	`LocalFree()`
`LocalReAlloc()`	`LocalFree()`
`GlobalAlloc()`	`GlobalFree()`
`GlobalReAlloc()`	`GlobalFree()`
`VirtualAlloc()`	`VirtualFree()`
`VirtualAllocEx()`	`VirtualFreeEx()`
`VirtualAllocExNuma()`	`VirtualFreeEx()`
`HeapAlloc()`	`HeapFree()`
`HeapReAlloc()`	`HeapFree()`

示例 - 使用了不正确的函数来释放内存

#ifdef _WIN32_
#include <windows.h>
#else
#define _WIN32_
typedef void *HANDLE;
typedef HANDLE HGLOBAL;
typedef HANDLE HLOCAL;
typedef unsigned int UINT;
extern HLOCAL LocalAlloc(UINT uFlags, UINT uBytes);
extern HLOCAL LocalFree(HLOCAL hMem);
extern HGLOBAL GlobalFree(HGLOBAL hMem);
#endif

#define SIZE9 9


void func(void)
{
	/* Memory allocation */
    HLOCAL p = LocalAlloc(0x0000, SIZE9);
	
    if (p) {
		/* Memory deallocation. */
        GlobalFree(p); //Noncompliant
		
    }
}

在此示例中，使用了 LocallAlloc() 来分配内存。然后程序错误地使用 GlobalFree() 来释放内存。

更正 - 正确配对 Windows 分配和释放函数

当您使用 LocalAllocate() 分配内存时，请使用 LocalFree() 释放内存。

#ifdef _WIN32_
#include <windows.h>
#else
#define _WIN32_
typedef void *HANDLE;
typedef HANDLE HGLOBAL;
typedef HANDLE HLOCAL;
typedef unsigned int UINT;
extern HLOCAL LocalAlloc(UINT uFlags, UINT uBytes);
extern HLOCAL LocalFree(HLOCAL hMem);
extern HGLOBAL GlobalFree(HGLOBAL hMem);
#endif

#define SIZE9 9
void func(void)
{
	/* Memory allocation */
    HLOCAL p = LocalAlloc(0x0000, SIZE9);
    if (p) {
		/* Memory deallocation. */
        LocalFree(p);  
    }
}

检查信息

组：Rule 51.Microsoft Windows (WIN)

版本历史记录

在 R2019a 中推出

另请参阅

检查 SEI CERT-C (-cert-c)

主题

检查并审查编码标准违规

外部网站

WIN30-C

¹ This software has been created by MathWorks incorporating portions of: the “SEI CERT-C Website,” © 2017 Carnegie Mellon University, the SEI CERT-C++ Web site © 2017 Carnegie Mellon University, ”SEI CERT C Coding Standard – Rules for Developing safe, Reliable and Secure systems – 2016 Edition,” © 2016 Carnegie Mellon University, and “SEI CERT C++ Coding Standard – Rules for Developing safe, Reliable and Secure systems in C++ – 2016 Edition” © 2016 Carnegie Mellon University, with special permission from its Software Engineering Institute.

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