共用方式為


basic_filebuf::close

Closes a file.

basic_filebuf<Elem, Tr> *close( );

Return Value

The member function returns a null pointer if the file pointer is a null pointer.

Remarks

close calls fclose(fp). If that function returns a nonzero value, the function returns a null pointer. Otherwise, it returns this to indicate that the file was successfully closed.

For a wide stream, if any insertions have occurred since the stream was opened, or since the last call to streampos, the function calls overflow. It also inserts any sequence needed to restore the initial conversion state, by using the file conversion facet fac to call fac.unshift as needed. Each element byte of type char thus produced is written to the associated stream designated by the file pointer fp as if by successive calls of the form fputc(byte, fp). If the call to fac.unshift or any write fails, the function does not succeed.

Example

The following sample assumes two files in the current directory: basic_filebuf_close.txt (contents is "testing") and iotest.txt (contents is "ssss").

// basic_filebuf_close.cpp
// compile with: /EHsc
#include <fstream>
#include <iostream>

int main() {
   using namespace std;
   ifstream file;
   basic_ifstream <wchar_t> wfile;
   char c;
   // Open and close with a basic_filebuf
   file.rdbuf()->open( "basic_filebuf_close.txt", ios::in );
   file >> c;
   cout << c << endl;
   file.rdbuf( )->close( );

   // Open/close directly
   file.open( "iotest.txt" );
   file >> c;
   cout << c << endl;
   file.close( );

   // open a file with a wide character name
   wfile.open( L"iotest.txt" );

   // Open and close a nonexistent with a basic_filebuf
   file.rdbuf()->open( "ziotest.txt", ios::in );
   cout << file.fail() << endl;
   file.rdbuf( )->close( );

   // Open/close directly
   file.open( "ziotest.txt" );
   cout << file.fail() << endl;
   file.close( );
}
t
s
0
1

Requirements

Header: <fstream>

Namespace: std

See Also

Reference

basic_filebuf Class

iostream Programming

iostreams Conventions