std::basic_streambuf::showmanyc

 

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std::basic_streambuf

Public member functions

basic_streambuf::~basic_streambuf

Locales

basic_streambuf::pubimbue

basic_streambuf::getloc

Positioning

basic_streambuf::pubsetbuf

basic_streambuf::pubseekoff

basic_streambuf::pubseekpos

basic_streambuf::pubsync

Get area

basic_streambuf::in_avail

basic_streambuf::snextc

basic_streambuf::sbumpc

basic_streambuf::sgetc

basic_streambuf::sgetn

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basic_streambuf::sputc

basic_streambuf::sputn

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basic_streambuf::sputbackc

basic_streambuf::sungetc

Protected member functions

basic_streambuf::basic_streambuf

basic_streambuf::operator= (C++11)

basic_streambuf::swap (C++11)

Locales

basic_streambuf::imbue

Positioning

basic_streambuf::setbuf

basic_streambuf::seekoff

basic_streambuf::seekpos

basic_streambuf::sync

Get area

basic_streambuf::showmanyc

basic_streambuf::underflow

basic_streambuf::uflow

basic_streambuf::xsgetn

basic_streambuf::ebackbasic_streambuf::gptrbasic_streambuf::egptr

basic_streambuf::gbump

basic_streambuf::setg

Put area

basic_streambuf::xsputn

basic_streambuf::overflow

basic_streambuf::pbasebasic_streambuf::pptrbasic_streambuf::epptr

basic_streambuf::pbump

basic_streambuf::setp

Putback

basic_streambuf::pbackfail

 

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() 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 definitely return Traits::eof.

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

See also

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