# std::basic_fstream<CharT,Traits>::basic_fstream

From cppreference.com
< cpp‎ | io‎ | basic fstream

basic_fstream(); | (1) |
explicit basic_fstream( const char* filename, std::ios_base::openmode mode = ios_base::in|ios_base::out ); | (2) |
explicit basic_fstream( const std::filesystem::path::value_type* filename, std::ios_base::openmode mode = ios_base::in|ios_base::out ); | (3) | (since C++17)
explicit basic_fstream( const std::string& filename, std::ios_base::openmode mode = ios_base::in|ios_base::out ); | (4) | (since C++11)
explicit basic_fstream( const std::filesystem::path& filename, std::ios_base::openmode mode = ios_base::in|ios_base::out ); | (5) | (since C++17)
basic_fstream( basic_fstream&& other ); | (6) | (since C++11)
basic_fstream( const basic_fstream& rhs) = delete; | (7) | (since C++11)

Constructs new file stream.

1) Default constructor: constructs a stream that is not associated with a file: default-constructs the std::basic_filebuf and constructs the base with the pointer to this default-constructed std::basic_filebuf member.
2-3) First, performs the same steps as the default constructor, then associates the stream with a file by calling rdbuf()->open(filename, mode) (see std::basic_filebuf::open for the details on the effects of that call). If the open() call returns a null pointer, sets setstate(failbit). Overload (3) is only provided if std::filesystem::path::value_type is not char. (since C++17)
4-5) Same as basic_fstream(filename.c_str(), mode).
6) Move constructor. First, move-constructs the base class from `other` (which does not affect the `rdbuf()` pointer), then move-constructs the std::basic_filebuf member, then calls this->set_rdbuf() to install the new `basic_filebuf` as the rdbuf() pointer in the base class.
7) The copy-constructor is deleted: this class is not copyable.

### Parameters

filename | - | the name of the file to be opened

mode

-

specifies stream open mode. It is bitmask type, the following constants are defined:

Constant | Explanation
`app` | seek to the end of stream before each write
`binary` | open in binary mode
`in` | open for reading
`out` | open for writing
`trunc` | discard the contents of the stream when opening
`ate` | seek to the end of stream immediately after open

other | - | another file stream to use as source

### Example

Run this code

    #include <fstream>
    #include <utility>
    #include <string>
    int main()
    {
        std::fstream f0;
        std::fstream f1("test.bin", std::ios::binary);
        std::string name = "example.txt";
        std::fstream f2(name);
        std::fstream f3(std::move(f1));
    }

### See also

open | opens a file and associates it with the stream (public member function)
open | opens a file and configures it as the associated character sequence (public member function of `std::basic_filebuf<CharT,Traits>`)
set_rdbuf | replaces the `rdbuf` without clearing its error state (protected member function)
(constructor) | constructs the object (public member function of `std::basic_iostream<CharT,Traits>`)

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/io/basic_fstream/basic_fstream&oldid=50830"