任何用于测试扩展 C/C++ 的实用程序#定义宏？

发布于 2024-09-05 14:32:00 字数 770 浏览 3 评论 0原文

看来我经常花费太多时间试图让#define 宏完全按照我想要的方式进行。我将在下面发布我当前的困境，感谢任何帮助。但真正更大的问题是，是否有人可以推荐任何实用程序来快速显示宏实际上在做什么？如果我能看到问题所在，那么即使是缓慢的试错过程也会变得更快。

目前，我正在从我制作的 DLL 中动态加载一长串函数。按照我设置的方式，函数指针与导出函数具有相同的名称，并且用于原型化它们的 typedef 具有相同的名称，但前面带有下划线。所以我想使用定义来简化一长串函数指针的赋值。

例如，在下面的代码语句中，“hexdump”是 typedef 函数点的名称，也是函数的名称，而 _hexdump 是 typedef 的名称。如果 GetProcAddress() 失败，则失败计数器会递增。

if (!(hexdump = (_hexdump)GetProcAddress(h, "hexdump"))) --iFail;

因此，假设我想用宏替换上面的每一行，就像这样......

GETADDR_FOR(hexdump )

这是迄今为止我想到的最好的。它不起作用（我的//评论只是为了防止消息中的文本格式）...

// #define GETADDR_FOR(a) if (!(a = (#_#a)GetProcAddress(h, "/""#a"/""))) --iFail;

再说一次，虽然我很高兴了解我犯了哪些愚蠢的错误，但这将使我有一天只需插入我的宏，它就会向我显示我的方法的错误。

原文

It seems I often spend way too much time trying to get a #define macro to do exactly what i want. I'll post my current dilemma below and any help is appreciated. But really the bigger question is whether there is any utility someone could recommend, to quickly display what a macro is actually doing? It seems like even the slow trial and error process would go much faster if I could see what is wrong.

Currently, I'm dynamically loading a long list of functions from a DLL I made. The way I've set things up, the function pointers have the same nanes as the exported functions, and the typedef(s) used to prototype them have the same names, but with a prepended underscore. So I want to use a define to simplify assignments of a long long list of function pointers.

For example, In the code statement below, 'hexdump' is the name of a typedef'd function point, and is also the name of the function, while _hexdump is the name of the typedef. If GetProcAddress() fails, a failure counter in incremented.

if (!(hexdump = (_hexdump)GetProcAddress(h, "hexdump"))) --iFail;

So let's say I'd like to replace each line like the above with a macro, like this...

GETADDR_FOR(hexdump )

Well this is the best I've come up with so far. It doesn't work (my // comment is just to prevent text formatting in the message)...

// #define GETADDR_FOR(a) if (!(a = (#_#a)GetProcAddress(h, "/""#a"/""))) --iFail;

And again, while I'd APPRECIATE an insight into what silly mistake I've made, it would make my day to have a utility that would show me the error of my ways, by simply plugging in my macro.

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夜唯美灬不弃 2024-09-12 14:32:00

转至https://godbolt.org/。在左窗格中输入代码，然后选择编译器作为 gcc，将参数设置为右窗格中的 -E。您的预处理代码将显示在右侧。

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蓦然回首 2024-09-12 14:32:00

您只需通过预处理器运行您的代码，它将显示它将被扩展成什么（或根据需要吐出错误）：

$ cat a.c
#define GETADDR_FOR(a) if (!(a = (#_#a)GetProcAddress(h, "/""#a"/""))) 
GETADDR_FOR(hexdump)

$ gcc -E a.c
# 1 "a.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "a.c"
a.c:1:36: error: '#' is not followed by a macro parameter

GETADDR_FOR(hexdump)

在 GCC 中，gcc -E foo.c 仅预处理文件。

Visual Studio 使用 /P 参数。

You can just run your code through the preprocessor, which will show you what it will be expanded into (or spit out errors as necessary):

$ cat a.c
#define GETADDR_FOR(a) if (!(a = (#_#a)GetProcAddress(h, "/""#a"/""))) 
GETADDR_FOR(hexdump)

$ gcc -E a.c
# 1 "a.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "a.c"
a.c:1:36: error: '#' is not followed by a macro parameter

GETADDR_FOR(hexdump)

In GCC, it's gcc -E foo.c to only preprocess the file.

Visual Studio uses the /P argument.

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掩饰不了的爱 2024-09-12 14:32:00

http://visualstudiogallery.msdn.microsoft.com/59a2438f-ba4a-4945 -a407-a1a295598088 - 用于扩展宏的 Visual Studio 插件

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生寂 2024-09-12 14:32:00

您似乎对 C 预处理器宏中字符串化或标记粘贴的确切语法感到困惑。

您可能会发现此页面关于C 预处理器宏通常很有帮助。

特别是，我认为这个宏应该这样读：

#define GETADDR_FOR(a) if (!(a = (_##a)GetProcAddress(h, #a))) --iFail

应该跳过尾随的 ; ，因为您可能会将其键入为 GETADDR_FOR(hexdump);，如果您不这样做它在你的 C 代码中看起来不会很奇怪并且会混淆许多语法荧光笔。

正如其他人提到的，gcc -E 将运行预处理器并跳过其他编译步骤。这对于调试预处理器问题很有用。

You appear to be confused about what the exact syntax is for stringifying or token pasting in C preprocessor macros.

You might find this page about C preprocessor macros in general helpful.

In particular, I think this macro should read like this:

#define GETADDR_FOR(a) if (!(a = (_##a)GetProcAddress(h, #a))) --iFail

The trailing ; should be skipped because you will likely be typing this as GETADDR_FOR(hexdump);, and if you don't it will look very strange in your C code and confuse many syntax highlighters.

And as someone else mentioned gcc -E will run the preprocessor and skip the other compilation steps. This is useful for debugging preprocessor problems.

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