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# std::basic_streambuf::showmanyc

From cppreference.com
< cpp‎ | io‎ | basic streambuf

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.

### [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.

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

### [edit] Example

| This section is incomplete Reason: no example

### [edit] See also

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

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- Todo no example