The Microsoft Input/Output Stream Classes (iostream.hlp) (Table of Contents; Topic list)
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ofstream::ofstream
ofstream                                    Up Contents Index Back
──The Microsoft iostream Classes────────────────────────────────────────────
 
  ofstream();
  ofstream( const char* szName, int nMode = ios::out,
            int nProt = filebuf::openprot );
  ofstream( filedesc fd );
  ofstream( filedesc fd, char* pch, int nLength );
 
  Parameter   Description
 
  <szName>    The name of the file to be opened during construction.
 
  <nMode>     An integer that contains mode bits defined as ios
              enumerators that can be combined with the bitwise-OR (|)
              operator:
 
              Value            Meaning
 
              ios::app         The function performs a seek to the end of
                               file. When new bytes are written to the
                               file, they are always appended to the end,
                               even if the position is moved with the
                               ostream::seekp function.
 
              ios::ate         The function performs a seek to the end of
                               file. When the first new byte is written to
                               the file, it is appended to the end, but
                               when subsequent bytes are written, they are
                               written to the current position.
 
              ios::in          If this mode is specified, then the
                               original file (if it exists), will not be
                               truncated.
 
              ios::out         The file is opened for output (implied for
                               all ofstream objects).
 
              ios::trunc       If the file already exists, its contents
                               are discarded. This mode is implied if
                               ios::out is specified and ios::ate,
                               ios::app, and ios:in are not specified.
 
              ios::nocreate    If the file does not already exist, the
                               function fails.
 
              ios::noreplace   If the file already exists, the function
                               fails.
 
              ios::binary      Opens the file in binary mode (the default
                               is text mode).
 
  <nProt>     The file protection specification; defaults to the static
              integer filebuf::openprot that is equivalent to
              filebuf::sh_compat. The possible <nProt> values are:
 
              Value                Meaning
 
              filebuf::sh_compat   Compatibility share mode.
 
              filebuf::sh_none     Exclusive mode; no sharing.
 
              filebuf::sh_read     Read sharing allowed.
 
              filebuf::sh_write    Write sharing allowed.
 
              The filebuf::sh_read and filebuf::sh_write modes can be
              combined with the logical OR (|) operator.
 
  <fd>        A file descriptor as returned by a call to the run-time
              function _open or _sopen. filedesc is a typedef equivalent
              to int.
 
  <pch>       Pointer to a previously allocated reserve area of length
              <nLength>. A NULL value (or <nLength> = 0) indicates that
              the stream will be unbuffered.
 
  <nLength>   The length (in bytes) of the reserve area (0 = unbuffered).
 
  Remarks
 
  The four ofstream constructors are described as follows:
  Constructor                         Description
 
  ofstream()                          Constructs an ofstream object
                                      without opening a file.
 
  ofstream( const char*, int, int )   Contructs an ofstream object,
                                      opening the specified file.
 
  ofstream( filedesc )                Constructs an ofstream object that
                                      is attached to an open file.
 
  ofstream( filedesc, char*, int )    Constructs an ofstream object that
                                      is associated with a filebuf object.
                                      The filebuf object is attached to an
                                      open file and to a specified reserve
                                      area.
 
  All ofstream constructors construct a filebuf object. The first three
  use an internally allocated reserve area, but the fourth uses a
  user-allocated area. The user-allocated area is not automatically
  released during destruction.
 
 
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