帮你解析复杂的C语言声明

      很多C/C++的初学者，常常被一些复杂的声明语句弄得晕头转向，满头雾水。比如说：char *(*(*a[])())()，这个声明是什么意思呢？

     不用抓耳挠腮，在linux环境下，有一个工具能帮我们解析，它就是cdecl 。它能在C/C++声明和英语间转换。让我们先看看man cdecl里的描述吧：

DESCRIPTION
       Cdecl  (and c++decl) is a program for encoding and decoding C (or C++) type declarations.  The C language is based on the (draft proposed) X3J11 ANSI Standard; optionally, the C language may be based on the pre- ANSI  definition  defined  by  Kernighan  &  Ritchie’s The C Programming Language book, or the C language  defined by the Ritchie PDP-11 C compiler.  The C++ language is based on Bjarne Stroustrup’s The C++  Pro-gramming Language, plus the version 2.0 additions to the language.

     很容易用：键入cdecl命令，进入交互界面：

# cdecl
Type `help' or `?' for help
cdecl>

这时键入命令：

explain char *(*(*a[])())()

看看输出什么了：

declare a as array of pointer to function returning pointer to function returning pointer to char
cdecl>

反过来，我们把输出的英文当命令，再执行一次看看：

cdecl> declare a as array of pointer to function returning pointer to function returning pointer to char
char *(*(*a[])())()
cdecl>

     好用吧，如果有不明白，就help一下。

2010-12-28 于 杭州