std::basic_fstream::is_open
From cppreference.com
< cpp | io | basic fstream
| 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 |
[edit] Parameters
(none)
[edit] Return value
true if the file stream has an associated file, false otherwise
[edit] Example
Run this code
#include <string> #include <fstream> #include <iostream> int main() { std::string filename = "some_file"; std::fstream fs(filename, std::ios::in); std::cout << std::boolalpha; std::cout << "fs.is_open() = " << fs.is_open() << '\n'; if(!fs.is_open()) { fs.clear(); fs.open(filename, std::ios::out); std::cout << "fs.is_open() = " << fs.is_open() << '\n'; } }
Possible output:
fs.is_open() = false fs.is_open() = true
[edit] See also
| opens a file and associates it with the stream (public member function) |
|
| closes the associated file (public member function) |