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std::basic_ifstream::open(3)  C++ Standard Libary std::basic_ifstream::open(3)

NAME
       std::basic_ifstream::open - std::basic_ifstream::open

Synopsis
	  void open( const char* filename,

		     std::ios_base::openmode mode			(1)

			 = std::ios_base::in );
	  void open( const std::filesystem::path::value_type* filename,

		     std::ios_base::openmode   mode			   (2)
       (since C++17)

			 = std::ios_base::in );
	  void open( const std::string&	filename,

		     std::ios_base::openmode  mode			   (3)
       (since C++11)

			 = std::ios_base::in );
	  void open( const std::filesystem::path& filename,

		     std::ios_base::openmode   mode			   (4)
       (since C++17)

			 = std::ios_base::in );

	  Opens	and associates the file	 with  name  filename  with  the  file
       stream.

	  Calls	clear()	on success. Calls setstate(failbit) on failure.

	  1,2)	Effectively calls rdbuf()->open(filename, mode | ios_base::in)
       (see
	  std::basic_filebuf::open for the details  on	the  effects  of  that
       call).
	  Overload  (2)	 is only provided if std::filesystem::path::value_type
       is not char.
	  (since C++17)
	  3,4) Effectively calls (1,2) as if by	open(filename.c_str(), mode).

Parameters
	  filename - the name of the file to be	opened
		     specifies stream open mode. It is a BitmaskType, the fol-
       lowing constants
		     are defined:

		     Constant	       Explanation
		     app	       seek to the end of stream  before  each
       write
	  mode	   - 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
		     noreplace (C++23) open in exclusive mode

Return value
	  (none)

Example
	   This	section	is incomplete
	   Reason: no example

	  Defect reports

	  The following	behavior-changing defect reports were applied retroac-
       tively to
	  previously published C++ standards.

	    DR	     Applied	to		  Behavior    as     published
       Correct behavior
	  LWG  22   C++98	it  was	unclear	how error state	changes	upon a
       the error state is
			     successful					  open
       unchanged
	  LWG 409 C++98	     the error state was unchanged upon	a	    it
       is cleared^[1]
			     successful	open

	   1.  The resolution of LWG issue #22 is overriden.

See also
	  is_open checks if the	stream has an associated file
		  (public member function)
	  close	  closes the associated	file
		  (public member function)
	  open	   opens  a file and configures	it as the associated character
       sequence
		  (public member function of std::basic_filebuf<CharT,Traits>)

Category:
	    * Todo no example

http://cppreference.com		  2024.06.10	  std::basic_ifstream::open(3)

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