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std::basic_streambuf::showmanyc

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< cpp‎ | io‎ | basic streambuf
 
 
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(deprecated in C++98)
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(C++11)
 
 
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.

Contents

[edit] Parameters

(none)

[edit] 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 definitely 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".

[edit] 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"

[edit] Example

[edit] See also

obtains the number of characters immediately available in the get area
(public member function) [edit]
[virtual]
optionally provides the number of characters available for input from the file
(virtual protected member function of std::basic_filebuf) [edit]