NAME

std::basic_ifstream::is_open - std::basic_ifstream::is_open

Synopsis

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().

Parameters

(none)

Return value

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

Example

// Run this code

#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

open opens a file and associates it with the stream
(public member function)
close closes the associated file
(public member function)