| fstream::is_open |
public member function |
Check if a file is open
Returns true if the stream is currently associated with a file, and false otherwise.
To determine this, the function calls: rdbuf()->is_open()
The stream is associated with a file if either a previous call to member open succeeded or if the object was successfully constructed using the parameterized constructor, and close has not been called since.
Parameters
none
Return Value
true if a file is open, i.e. associated to this stream object.
false otherwise.
Example
// fstream::is_open
#include <iostream>
#include <fstream>
using namespace std;
int main () {
fstream filestr;
filestr.open ("test.txt");
if (filestr.is_open())
{
filestr << "File successfully open";
filestr.close();
}
else
{
cout << "Error opening file";
}
return 0;
} |
This example uses
is_open to check whether the file has successfully been opened; If so, it writes a sentence to the file, otherwise it prints out an error message.
Basic template member declaration
( basic_fstream<charT,traits> )
See also
