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Describes an object that controls insertion of elements and encoded objects into a stream buffer of class basic_filebuf< Elem, Tr> , with elements of type Elem , whose character traits are determined by the class Tr . For more information, see basic_filebuf .

Syntax

template <class Elem, class Tr = char_traits<Elem>>
class basic_ofstream : public basic_ostream<Elem, Tr>
Parameters
The basic element of the file buffer.

The traits of the basic element of the file buffer (usually char_traits<Elem>).

Remarks
When the wchar_t specialization of basic_ofstream writes to the file, if the file is opened in text mode it will write an MBCS sequence. The internal representation will use a buffer of wchar_t characters.
The object stores an object of class basic_filebuf< Elem, Tr>.
Example
The following example shows how to create a basic_ofstream object and write text to it.
// basic_ofstream_class.cpp
// compile with: /EHsc
#include <fstream>
using namespace std;
int main(int argc, char **argv)
    ofstream ofs("ofstream.txt");
    if (!ofs.bad())
        ofs << "Writing to a basic_ofstream object..." << endl;
        ofs.close();
Constructors
Constructor
Description
 basic_ofstream::basic_ofstream
Creates an object of type basic_ofstream.
basic_ofstream();
explicit basic_ofstream(
    const char* _Filename,
    ios_base::openmode _Mode = ios_base::out,
    int _Prot = (int)ios_base::_Openprot);
explicit basic_ofstream(
    const wchar_t* _Filename,
    ios_base::openmode _Mode = ios_base::out,
    int _Prot = (int)ios_base::_Openprot);
basic_ofstream(
    basic_ofstream&& right);
Parameters
_Filename

The name of the file to open.
_Mode

One of the enumerations in ios_base::openmode.
_Prot

The default file opening protection, equivalent to the shflag parameter in _fsopen, _wfsopen.
right

The rvalue reference to the basic_ofstream object being used to initialize this basic_ofstream object.
Remarks
The first constructor initializes the base class by calling basic_ostream(sb), where sb is the stored object of class basic_filebuf< Elem, Tr>. It also initializes sb by calling basic_filebuf< Elem, Tr>.
The second and third constructors initialize the base class by calling basic_ostream( sb). It also initializes sb by calling basic_filebuf< Elem, Tr> and then sb.open( _Filename, _Mode | ios_base::out). If the latter function returns a NULL pointer, the constructor calls setstate(failbit).
The fourth constructor is a copy function. It initializes the object with the contents of right, treated as an rvalue reference.
For more information, see basic_ostream, open, and setstate.
Example
The following example shows how to create a basic_ofstream object and write text to it.
// basic_ofstream_ctor.cpp
// compile with: /EHsc
#include <fstream>
using namespace std;
int main(int argc, char **argv)
    ofstream ofs("C:\\ofstream.txt");
    if (!ofs.bad())
        ofs << "Writing to a basic_ofstream object..." << endl;
        ofs.close();
 basic_ofstream::close
Closes a file.
void close();
Remarks
The member function calls rdbuf->close. For more information, see rdbuf and close.
Example
See basic_filebuf::close for an example that uses close.
 basic_ofstream::is_open
Indicates whether a file is open.
bool is_open() const;
Return Value
true if the file is open, false otherwise.
Remarks
The member function returns rdbuf->is_open. For more information, see rdbuf and is_open.
Example
// basic_ofstream_is_open.cpp
// compile with: /EHsc
#include <fstream>
#include <iostream>
int main( )
   using namespace std;
   ifstream file;
   // Open and close with a basic_filebuf
   file.rdbuf( )->open( "basic_ofstream_is_open.txt", ios::in );
   file.close( );
   if (file.is_open())
      cout << "it's open" << endl;
      cout << "it's closed" << endl;
 basic_ofstream::open
Opens a file.
void open(
    const char* _Filename,
    ios_base::openmode _Mode = ios_base::out,
    int _Prot = (int)ios_base::_Openprot);
void open(
    const char* _Filename,
    ios_base::openmode _Mode);
void open(
    const wchar_t* _Filename,
    ios_base::openmode _Mode = ios_base::out,
    int _Prot = (int)ios_base::_Openprot);
void open(
    const wchar_t* _Filename,
    ios_base::openmode _Mode);
Parameters
_Filename

The name of the file to open.
_Mode

One of the enumerations in ios_base::openmode.
_Prot

The default file opening protection, equivalent to the shflag parameter in _fsopen, _wfsopen.
Remarks
The member function calls rdbuf -> open(_ Filename, _Mode | ios_base::out). If that function returns a NULL pointer, the function calls setstate(failbit).
For more information, see rdbuf, open, and setstate.
Example
See basic_filebuf::open for an example that uses open.
 basic_ofstream::operator=
Assigns the content of this stream object. This is a move assignment involving an rvalue reference that doesn't leave a copy behind.
basic_ofstream& operator=(basic_ofstream&& right);
Parameters
right

An rvalue reference to a basic_ofstream object.
Return Value
Returns *this.
Remarks
The member operator replaces the contents of the object by using the contents of right, treated as an rvalue reference.
 basic_ofstream::rdbuf
Returns the address of the stored stream buffer.
basic_filebuf<Elem, Tr> *rdbuf() const
Return Value
Returns the address of the stored stream buffer.
Example
See basic_filebuf::close for an example that uses rdbuf.
 basic_ofstream::swap
Exchanges the contents of two basic_ofstream objects.
void swap(basic_ofstream& right);
Parameters
right

An lvalue reference to another basic_ofstream object.
Remarks
The member function exchanges the contents of this object for the contents of right.
See also
basic_ostream Class

Thread Safety in the C++ Standard Library

iostream Programming

iostreams Conventions