Re: Why string's c_str()? [Overloading const char *()]

From:
Paavo Helde <myfirstname@osa.pri.ee>
Newsgroups:
comp.lang.c++
Date:
Sun, 03 Nov 2013 02:33:16 -0600
Message-ID:
<XnsA26D6B59C965Bmyfirstnameosapriee@216.196.109.131>
DSF <notavalid@address.here> wrote in
news:2rva79leu30dpkocg578pne9t3h8jvbv56@4ax.com:

  
  Why do I care? Because I use raw pointers all the time. I write
Windows code, and 70% of the API calls involve a pointer to a
character string, pointer to a structure, pointer to a buffer, etc.


That's because Windows API is defined in terms of C and not C++.

In C++ one usually writes wrappers or uses other C++ libraries in order
to encapsulate a C API, so the rest of the code can use normal C++ style.
In the wrapper code you need pointers and buffers indeed, but this is a
localized one-time activity.

Example: encapsulate getcwd():

sdt::string My_getcwd() {
    wchar_t buff[MAX_PATH];
    DWORD n = ::GetCurrentDirectoryW(MAX_PATH, buff);
    if (n==0 || n>MAX_PATH) {
        throw MyException("my_getcwd failed: " + MyGetLastErrorString());
    }
    return Win2UtfFileName(std::wstring(buff, n));
}

Here, Win2UtfFileName() is another wrapper function wrapping
WideCharToMultiByte() on Windows an converting Windows UTF-16 to more
portable UTF-8, but that's not the main point here.

Third-party libraries like boost::filesystem probably do this better. But
in any case you should use C++ interfaces in the bulk of your codebase
and not struggling with C pointer-and-buffer madness all the time.

Cheers
Paavo

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