streambuf::in_avail


public member function
streamsize in_avail ( );

Get number of characters available to read

Returns the number of characters available to read. This value depends on whether there are read positions directly available at the get pointer:
  • If the get pointer has a value and this is less than the end pointer: The function returns the number of characters directly available at the get pointer before the end pointer (returns egptr()-gptr() without calling any virtual member function).
  • If the get pointer is either null or has reached the end pointer: The function returns the number of characters expected to be available after an underflow. This is obtained by calling the protected virtual member function showmanyc.


Parameters

none

Return Value

The number of characters available in the input buffer.
This is a value of integral type streamsize.

Example

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// in_avail () example
#include <iostream>
using namespace std;

int main () {

  streamsize size;
  char ch;

  streambuf * pbuf;
  pbuf = cin.rdbuf();

  cout << "Please enter some characters: ";
  cin >> ch;

  size = pbuf->in_avail();

  cout << "The first character you entered is: " << ch << endl;
  cout << size << " additional characters in input buffer" << endl;

  return 0;
}


Basic template member declaration

( basic_streambuf<charT,traits> )
  
streamsize in_avail ( );


See also

streambuf::showmanyc Get number of characters available in the sequence (virtual protected member function)
streambuf::gptr Pointer to current position of input sequence (protected member function)
streambuf::egptr Pointer to end of input sequence (protected member function)