Checks if the file stream has an associated file.

Effectively callsrdbuf()->is_open().

[edit]Parameters

(none)

[edit]Return value

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

[edit]Example

#include <fstream>#include <iostream>#include <string> 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';}}

fs.is_open() = falsefs.is_open() = true

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit]See also

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