std::fclose (3) - Linux Manuals
Defined in header <cstdio>
int fclose( std::FILE* stream );
Closes the given file stream. Any unwritten buffered data are flushed to the OS. Any unread buffered data are discarded.
Whether or not the operation succeeds, the stream is no longer associated with a file, and the buffer allocated by std::setbuf or std::setvbuf, if any, is also disassociated and deallocated if automatic allocation was used.
The behavior is undefined if the value of the pointer stream is used after fclose returns.
stream - the file stream to close
0 on success, EOF otherwise
// Run this code
close (public member function of std::basic_filebuf<CharT,Traits>)