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std::basic_ifstream::is_open

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< cpp‎ | io‎ | basic ifstream
Revision as of 22:12, 2 November 2012 by P12bot (Talk | contribs)

bool is_open();
(until C++11)
bool is_open() const;
(since C++11)

Checks if the file stream has an associated file.

Effectively calls rdbuf()->is_open().

Contents

Parameters

(none)

Return value

true if the file stream has an associated file, false otherwise

Example

#include <string>
#include <fstream>
#include <iostream>
//this file is called main.cpp
 
bool file_exists(const std::string& str)
{
   std::ifstream fs(str);
   return fs.is_open();
}
 
int main()
{
  std::boolalpha(std::cout);
  std::cout << file_exists("main.cpp")  << '\n'
            << file_exists("strange_file") << '\n';
}

Possible output:

true
false

See also

opens a file and associates it with the stream
(public member function) [edit]
closes the associated file
(public member function) [edit]