在哪里可以看到C ++字符串函数c_str的代码

Question

I want to see the code of c_str function in c++.

How can I see that-->

(1) In Intel Compiler (2) IN Visual Studio 2012 Compiler (3) In GCC/MinGW.

Answer 1

Open the <string> header file, and follow the trail of #include s until you find the basic_string<T> template. That's where the source of the c_str will be.

For example, in Visual Studio 2012 the function is located in the <xstring> header, and looks as follows:

const _Elem *c_str() const _NOEXCEPT
    {   // return pointer to null-terminated nonmutable array
    return (this->_Myptr());
    }

Answer 2

With a decent ide, you can right click the function and the select "Go to Definition". Visual studio has this option, so that will be the quickest for MSVC's implementation. For gcc (libstdc++), I like using there online doxygen docs . Here is a link to the implementation of c_str() . For intel, I believe they use libstdc++ (gcc's implementation).

Answer 3

With MinGW, you can find the header file at ...\\MinGW\\lib\\gcc\\mingw32\\4.7.1\\include\\c++\\debug\\string. The c_str() function is defined directly in that header, not in an include; I've placed the text below.

const _CharT* c_str() const _GLIBCXX_NOEXCEPT
    {
      const _CharT* __res = _Base::c_str();
      this->_M_invalidate_all();
      return __res;
    }

Answer 4

Rather than trying to find and open the include file where this function is defined (supposing it is defined in an include file—this is usually the case, but isn't required): what I usually do when I want to see the definition of a class is write a one line program which includes the appropriate header, and nothing else. Here:

#include <string>

(Yes, that's the complete program.) I then compile with the /E option (VC++) or the -E option (most other compilers), redirecting the output to a file, which I can then peruse at my leisure.

This is easy to do directly from the command line, but if you want to use VS, open up the properties on a source file which includes <string> , go to the entry C/C++ -> Command Line, and enter /E in the Additional Options pane. Then compile. The output will appear in the output window; click on it, then control-A followed by control-C, and you can paste it in whatever editor you please.

Either way, once you've got the preprocessor output in an editor, search from the top for c_str as a full word.

Answer 5

If your on linux or using MinGW or WSL if you create a file called string.txt
and put

#include <string>

and run cpp string.txt > string.txt from terminal or got to this site