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 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".

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 retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
underflow() is guaranteed not to extended the guarantee to allow
LWG 159 C++98 fail until at least
at least showmanyc() characters showmanyc() characters 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 input from the
showmanyc file
[virtual] (virtual protected member function of std::basic_filebuf<CharT,Traits>)

Category:¶

* Todo no example