basic_ifstream(); | (1) | |
explicit basic_ifstream( const char* filename,
ios_base::openmode mode = ios_base::in ); | (2) | |
explicit basic_ifstream( const string& filename,
ios_base::openmode mode = ios_base::in ); | (3) | (since C++11) |
basic_ifstream( basic_ifstream&& other ); | (4) | (since C++11) |
basic_ifstream( const basic_ifstream& rhs) = delete; | (5) | (since C++11) |
Constructs new file stream.
1) Default constructor: constructs a stream that is not associated with a file: default-constructs the
std::basic_filebuf and constructs the base with the pointer to this default-constructed std::basic_filebuf member. 2) First, performs the same steps as the default constructor, then associates the stream with a file by calling
rdbuf()->open(filename, mode | std::ios_base::in) (see std::basic_filebuf::open for the details on the effects of that call). If the open() call returns a null pointer, sets setstate(failbit). 3) Same as
basic_ifstream(filename.c_str(), mode). 4) Move constructor. First, move-constructs the base class from
other (which does not affect the rdbuf() pointer), then move-constructs the std::basic_filebuf member, then calls this->set_rdbuf() to install the new basic_filebuf as the rdbuf() pointer in the base class. 5) The copy-constructor is deleted: this class is not copyable.
Parameters
| filename | - | the name of the file to be opened | ||||||||||||||
| mode | - | specifies stream open mode. It is bitmask type, the following constants are defined:
| ||||||||||||||
| other | - | another file stream to use as source |
Example
#include <fstream>
#include <utility>
#include <string>
int main()
{
std::ifstream f0;
std::ifstream f1("test.bin", std::ios::binary);
std::string name = "example.txt";
std::ifstream f2(name);
std::ifstream f3(std::move(f1));
}See also
| opens a file and associates it with the stream (public member function) | |
| opens a file and configures it as the associated character sequence (public member function of std::basic_filebuf) | |
replaces the rdbuf without clearing its error state (protected member function) | |
| constructs the object (public member function of std::basic_istream) |
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