std::basic_streambuf<CharT,Traits>::in_avail
Min standard notice:
Returns the number of characters available in the get area. If a read position is available, effectively returns egptr() - gptr(), the size of the get area. In this case, the number of bytes returned is the number of bytes that can be extracted from the buffer without calling underflow().
# Declarations
std::streamsize in_avail();
# Return value
The number of characters available for non-blocking read (either the size of the get area or the number of characters ready for reading from the associated character sequence), or -1 if no characters are available in the associated sequence as far as showmanyc() can tell.
# Example
This section is incompleteReason: no example