void open( const char *filename,
ios_base::openmode mode = ios_base::in|ios_base::out ); | (1) | |
void open( const std::string &filename,
ios_base::openmode mode = ios_base::in|ios_base::out ); | (2) | (since C++11) |
Opens and associates the file with name filename with the file stream.
Calls setstate(failbit) on failure.
Calls clear() on success. | (since C++11) |
1) Effectively calls
rdbuf()->open(filename, mode). (see std::basic_filebuf::open for the details on the effects of that call) 2) Effectively calls (1) as if by
open(filename.c_str(), mode). Parameters
| filename | - | the name of the file to be opened | ||||||||||||||
| mode | - | specifies stream open mode. It is bitmask type, the following constants are defined:
|
Return value
(none).
Example
#include <string>
#include <fstream>
#include <iostream>
int main()
{
std::string filename = "example.123";
std::fstream fs;
fs.open(filename);
if(!fs.is_open())
{
fs.clear();
fs.open(filename, std::ios::out); //Create file.
fs.close();
fs.open(filename);
}
std::cout << std::boolalpha;
std::cout << "fs.is_open() = " << fs.is_open() << '\n';
std::cout << "fs.good() = " << fs.good() << '\n';
}See also
| checks if the stream has an associated file (public member function) | |
| closes the associated file (public member function) | |
| opens a file and configures it as the associated character sequence (public member function of std::basic_filebuf) |
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