How to open an std::fstream (ofstream or ifstream) with a unicode filename in C++?

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How to open an std::fstream (ofstream or ifstream) with a unicode filename in C++?

2023-03-31 23:14| 来源: 网络整理| 查看: 265

When working with filenames that contain non-ASCII characters in C++, it can be challenging to open an std::fstream (ofstream or ifstream) object with these filenames. The default string type in C++, std::string, uses an ASCII encoding, which may not be able to represent all characters in a Unicode filename. This can result in errors when attempting to open the file for reading or writing.

Method 1: Use wide-character filenames

To open an std::fstream (either ofstream or ifstream) with a Unicode filename in C++, you can use the wide-character filename functions. Here are the steps to do it:

Include the necessary headers: #include // for std::fstream #include // for std::codecvt_utf8_utf16 #include // for std::wstring_convert Convert the Unicode filename from wchar_t to std::string: std::wstring_convert converter; std::string filename = converter.to_bytes(L"unicode_filename.txt"); Open the file using the converted filename: std::fstream file(filename, std::ios::in | std::ios::binary); if (file.is_open()) { // do something with the file file.close(); } else { // handle error }

Here, we first create a std::wstring_convert object with std::codecvt_utf8_utf16 to convert the wchar_t filename to a UTF-8 std::string. Then, we use the converted filename to open the file with std::fstream. Finally, we check if the file is open and do something with it if it is, or handle the error if it is not.

Note that the std::ios::binary flag is used to open the file in binary mode, which is necessary for some file types (such as images or executables). If you don't need binary mode, you can omit this flag.

Here's the complete code:

#include // for std::fstream #include // for std::codecvt_utf8_utf16 #include // for std::wstring_convert int main() { std::wstring_convert converter; std::string filename = converter.to_bytes(L"unicode_filename.txt"); std::fstream file(filename, std::ios::in | std::ios::binary); if (file.is_open()) { // do something with the file file.close(); } else { // handle error } return 0; }Method 2: Convert filenames to a narrow string encoding

To open an std::fstream with a unicode filename, you can convert the filename to a narrow string encoding using the std::wstring_convert class. Here is an example code:

#include #include #include int main() { std::wstring filename = L"unicode_filename.txt"; std::wstring_convert> converter; std::string narrow_filename = converter.to_bytes(filename); std::ofstream outfile(narrow_filename); if (outfile.is_open()) { outfile

In this code, we first define the unicode filename as a std::wstring. We then create an instance of std::wstring_convert with the std::codecvt_utf8_utf16 codecvt facet to convert the filename to a narrow string encoding. We use the to_bytes member function of the std::wstring_convert instance to convert the filename to a std::string.

We then open an std::ofstream with the narrow filename and write some text to the file. We close the file and then open an std::ifstream with the same narrow filename. We read the contents of the file line by line and print them to the console.

Note that this method requires the codecvt header and the std::locale class. Also, it is important to properly handle any exceptions that may be thrown by the to_bytes member function.

Method 3: Use third-party libraries

To open an std::fstream with a Unicode filename in C++, you can use third-party libraries such as Boost.Filesystem or Windows API. Here are the steps to do it using Boost.Filesystem:

Include the necessary headers: #include #include Convert the Unicode filename to a boost::filesystem::path object: std::wstring filename = L"example_文件.txt"; boost::filesystem::path filepath(filename); Open the file using boost::filesystem::wifstream or boost::filesystem::wofstream: boost::filesystem::wofstream ofs(filepath); boost::filesystem::wifstream ifs(filepath);

Here's the complete code example:

#include #include #include int main() { std::wstring filename = L"example_文件.txt"; boost::filesystem::path filepath(filename); boost::filesystem::wofstream ofs(filepath); if (ofs.is_open()) { ofs

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How to open an std::fstream (ofstream or ifstream) with a unicode filename in C++?

How to open an std::fstream (ofstream or ifstream) with a unicode filename in C++?

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