basic_ofstreambasic_ostream
Supports writing into named files or other devices associated with a file descriptor.
#include <fstream> template<class charT, class traits = char_traits<charT> > class basic_ofstream : public basic_ostream<charT, traits>
The template class basic_ofstream<charT,traits> supports writing into named files or other devices associated with a file descriptor. It uses a basic_filebuf object to control the associated sequences. It inherits from basic_ostream and can therefore use all the formatted and unformatted output functions.
template<class charT, class traits = char_traits<charT> >
class basic_ofstream
: public basic_ostream<charT, traits> {
public:
typedef charT char_type;
typedef traits traits_type;
typedef typename traits::int_type int_type;
typedef typename traits::pos_type pos_type;
typedef typename traits::off_type off_type;
typedef basic_ios<charT, traits> ios_type;
basic_ofstream();
explicit basic_ofstream(const char *s,
ios_base::openmode mode =
ios_base::out,
long protection = 0666);
explicit basic_ofstream(int fd);
basic_ofstream(int fd, char_type* buf, int len);
virtual ~basic_ofstream();
basic_filebuf<charT, traits> *rdbuf() const;
bool is_open();
void open(const char *s, ios_base::openmode mode =
ios_type::out, long protection = 0666);
void close();
};
char_type
The type char_type is a synonym for the template parameter charT.
off_type
The type off_type is a synonym of type traits::off_type.
ofstream
The type ofstream is an instantiation of class basic_ofstream on type char:
typedef basic_ofstream<char> ofstream;
int_type
The type int_type is a synonym of type traits::in_type.
ios_type
The type ios_type is an instantiation of class basic_ios on type charT.
pos_type
The type pos_type is a synonym of type traits::pos_type.
traits_type
The type traits_type is a synonym for the template parameter traits.
wofstream
The type wofstream is an instantiation of class basic_ofstream on type wchar_t:
typedef basic_ofstream<wchar_t> wofstream;
basic_ofstream();
Constructs an object of class basic_ofstream<charT,traits>, initializing the base class basic_ostream with the associated file buffer, which is initialized by calling the basic_filebuf constructor basic_filebuf<charT,traits>(). After construction a file can be attached to the basic_ofstream object using the open member function.
basic_ofstream(const char* s,
ios_base::openmode mode= ios_base::in,
long protection= 0666);
Constructs an object of class basic_ofstream<charT,traits>, initializing the base class basic_ostream with the associated file buffer, which is initialized by calling the basic_filebuf constructor basic_filebuf<charT,traits>(). The constructor then calls the open function open(s,mode,protection) in order to attach the file whose name is pointed to by s, to the basic_ofstream object. The third argument, protection, is used as the file permissions. It does not appear in the Standard C++ description and is included as an extension. It determines the file read/write/execute permissions under UNIX. It is more limited under DOS since files are always readable and do not have special execute permission.
explicit basic_ofstream(int fd);
Constructs an object of class basic_ofstream<charT,traits>, initializing the base class basic_ostream with the associated file buffer, which is initialized by calling the basic_filebuf constructor basic_filebuf<charT,traits>(). The constructor then calls the basic_filebuf open function open(fd) in order to attach the file descriptor fd to the basic_ofstream object. This constructor is not described in the C++ standard, and is included as an extension in order to manipulate pipes, sockets, or other UNIX devices that can be accessed through file descriptors. If the function fails, it sets ios_base::failbit.
basic_ofstream(int fd, char_type* buf,int len);
Constructs an object of class basic_ofstream<charT,traits>, initializing the base class basic_ostream with the associated file buffer, which is initialized by calling the basic_filebuf constructor basic_filebuf<charT,traits>(). The constructor then calls the basic_filebuf open function open(fd) in order to attach the file descriptor fd to the basic_ofstream object. The underlying buffer is then replaced by calling the basic_filebuf member function setbuf with parameters buf and len. This constructor is not described in the C++ standard, and is included as an extension in order to manipulate pipes, sockets, or other UNIX devices that can be accessed through file descriptors. It also maintains compatibility with the old iostreams library. If the function fails, it sets ios_base::failbit.
virtual ~basic_ofstream();
Destroys an object of class basic_ofstream.
void close();
Calls the associated basic_filebuf function close() and if this function fails, it calls the basic_ios member function setstate(failbit).
bool is_open();
Calls the associated basic_filebuf function is_open() and returns its result.
void
open(const char* s,ios_base::openmode =
ios_base::out, long protection = 0666);
Calls the associated basic_filebuf function open(s,mode,protection) and, if this function fails opening the file, calls the basic_ios member function setstate(failbit). The third argument, protection, is used as the file permissions. It does not appear in the Standard C++ description and is included as an extension. It determines the file read/write/execute permissions under UNIX, and is more limited under DOS since files are always readable and do not have special execute permission.
basic_filebuf<charT,traits>* rdbuf() const;
Returns a pointer to the basic_filebuf associated with the stream.
See basic_fstream, basic_ifstream and basic_filebuf examples.
char_traits(3C++),ios_base(3C++), basic_ios(3C++), basic_filebuf(3C++), basic_ifstream(3C++), basic_fstream(3C++)
Working Paper for Draft Proposed International Standard for Information Systems--Programming Language C++, Section 27.8.1.8
ANSI X3J16/ISO WG21 Joint C++ Committee