basic_streambuf::_Sgetn_s
Extracts up to _Count characters from the input buffer and stores them in the provided buffer _Ptr.
streamsize _Sgetn_s(
char_type *_Ptr,
size_t _Ptr_size,
streamsize _Count
);
Parameters
_Ptr
The buffer to contain the extracted characters._Ptr_size
The size of _Ptr._Count
The number of elements to read.
Return Value
The number of elements read.
Remarks
The member function returns basic_streambuf::_Xsgetn_s(_Ptr, _Ptr_size, _Count).
Example
// basic_streambuf__Sgetn_s.cpp
// compile with: /EHsc
#include <iostream>
#include <fstream>
int main()
{
using namespace std;
ifstream myfile("basic_streambuf__Sgetn_s.txt", ios::in);
const int BUFSIZE = 10;
char a[BUFSIZE];
// Extract 3 characters from myfile and store them in a.
streamsize i = myfile.rdbuf()->_Sgetn_s(&a[0], BUFSIZE, 3);
a[i] = myfile.widen('\0');
// Display the size and contents of the buffer passed to sgetn.
cout << i << " " << a << endl;
// Display the contents of the original input buffer.
cout << myfile.rdbuf() << endl;
}
Input: basic_streambuf__Sgetn_s.txt
testing
Output
3 tes
ting
Requirements
Header: <streambuf>
Namespace: std