Visual Studio 2010(C ++):暂时禁止显示C4706警告 [英] Visual Studio 2010 (C++): suppress C4706 warning temporarily

问题描述

当在警告级别为/W4的情况下在Visual Studio 2010中编译以下C ++源文件时

When you compile the following C++ source file in Visual Studio 2010 with warning level /W4 enabled

#include <cstdio>  // for printf
#include <cstring> // for strcmp

char str0[] = "Hello";
char str1[] = "World";

int main()
{
    int result;

    if (result = strcmp(str0, str1)) // line 11
    {
        printf("Strings are different\n");
    }
}

您收到以下警告

警告C4706:条件表达式中的赋值

warning C4706: assignment within conditional expression

第11行.

我想在这个地方完全禁止显示此警告.因此，我尝试使用Google并找到了以下页面: http://msdn.microsoft. com/en-us/library/2c8f766e(v = VS.100).aspx

I want to suppress this warning exactly at this place. So I tried Google and found this page: http://msdn.microsoft.com/en-us/library/2c8f766e(v=VS.100).aspx

所以我将代码更改为以下代码-希望这可以解决问题:

So I changed the code to the following - hoping this would solve the problem:

#include <cstdio>  // for printf
#include <cstring> // for strcmp

char str0[] = "Hello";
char str1[] = "World";

int main()
{
    int result;

#pragma warning(push)
#pragma warning(disable : 4706)
    if (result = strcmp(str0, str1))
#pragma warning(pop)
    {
        printf("Strings are different\n");
    }
}

没有帮助.

此变体也没有帮助:

#include <cstdio>  // for printf
#include <cstring> // for strcmp

char str0[] = "Hello";
char str1[] = "World";

int main()
{
    int result;

#pragma warning(push)
#pragma warning(disable : 4706)
    if (result = strcmp(str0, str1))
    {
#pragma warning(pop)
        printf("Strings are different\n");
    }
}

为避免进一步询问，我在每次编译之前都已清理解决方案.因此，这可能不是问题.

To avoid one further inquiry: I cleaned the solution before each compilation. So this is probably not the fault.

因此，结论是:我该如何在这个位置精确抑制C4706?

So in conclusion: how do I suppress the C4706 exactly at this place?

编辑是的，可以重写-但是我真的很想知道为什么我尝试抑制警告的方式(在MSDN上正式记录)不起作用-错误在哪里?

Edit Yes, rewriting is possible - but I really want to know why the way I try to suppress the warning (that is documented officially on MSDN) doesn't work - where is the mistake?

推荐答案

在MSDN Libray中:

In MSDN Libray: http://msdn.microsoft.com/en-us/library/2c8f766e(v=VS.100).aspx, There is the section as follows.

对于4700-4999范围内的警告号 与代码生成相关联，警告的状态有效 当编译器遇到一个函数的大括号时， 对其余功能有效.在中使用警告语 更改具有更大数字的警告状态的功能 4699将仅在功能结束后生效.这 下面的示例显示警告语用正确的位置 禁用代码生成警告消息，然后将其还原.

For warning numbers in the range 4700-4999, which are the ones associated with code generation, the state of the warning in effect when the compiler encounters the open curly brace of a function will be in effect for the rest of the function. Using the warning pragma in the function to change the state of a warning that has a number larger than 4699 will only take effect after the end of the function. The following example shows the correct placement of warning pragmas to disable a code-generation warning message, and then to restore it.

因此，#pragma警告"仅适用于每种功能/方法.

So '#pragma warning' only works for an each function/method.

有关更多详细信息，请参见以下代码.

Please see the following code for more detail.

#include <cstdio>  // for printf
#include <cstring> // for strcmp

char str0[] = "Hello";
char str1[] = "World";

#pragma warning(push)
#pragma warning( disable : 4706 )
void func()
{
    int result;
    if (result = strcmp(str0, str1)) // No warning
    {
        printf("Strings are different\n");
    }
#pragma warning(pop)
}

int main()
{
    int result;

    if (result = strcmp(str0, str1)) // 4706 Warning.
    {
        printf("Strings are different\n");
    }
}

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