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std::basic_...f::showmanyc(3)  C++ Standard Libary std::basic_...f::showmanyc(3)

NAME
     std::basic_streambuf::showmanyc - std::basic_streambuf::showmanyc

Synopsis
	protected:
	virtual std::streamsize showmanyc();

	Estimates the number of characters available for input in the associated
     character
	sequence. underflow() is guaranteed not to return Traits::eof() or throw
     an
	exception until at least that many characters are extracted.

Parameters
	(none)

Return value
	The  number of characters that are certainly available in the associated
     character
	sequence, or -1 if showmanyc can determine, without  blocking,	that  no
     characters are
	available.  If	showmanyc returns -1, underflow() and uflow() will defi-
     nitely return
	Traits::eof or throw.

	The base class version returns 0, which has the meaning  of  "unsure  if
     there are
	characters available in the associated sequence".

Notes
	The  name of this function stands for "stream: how many characters?", so
     it is
	pronounced "S how many C", rather than "show many C".

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 be-
     havior
			   underflow() is guaranteed not to  extended the  guar-
     antee to allow
	LWG 159 C++98	   fail until			     at least
			   at least showmanyc() characters   showmanyc() charac-
     ters to be
			   are supplied 		     extracted

See also
	in_avail   obtains the number of characters immediately available in the
     get area
		  (public member function)
		  optionally provides the number of characters available for in-
     put from the
	showmanyc file
	[virtual]  (virtual  protected	member	function   of	std::basic_file-
     buf<CharT,Traits>)

Category:
	  * Todo no example

http://cppreference.com 	   2024.06.10	   std::basic_...f::showmanyc(3)
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