examples/manual/filebuf.cpp

/***************************************************************************
 *
 * filebuf.cpp - basic_filebuf example
 *
 * $Id: //stdlib/dev/examples/stdlib/manual/filebuf.cpp#17 $
 *
 ***************************************************************************
 *
 * Copyright (c) 1994-2005 Quovadx,  Inc., acting through its  Rogue Wave
 * Software division. Licensed under the Apache License, Version 2.0 (the
 * "License");  you may  not use this file except  in compliance with the
 * License.    You    may   obtain   a   copy   of    the   License    at
 * http://www.apache.org/licenses/LICENSE-2.0.    Unless   required    by
 * applicable law  or agreed to  in writing,  software  distributed under
 * the License is distributed on an "AS IS" BASIS,  WITHOUT WARRANTIES OR
 * CONDITIONS OF  ANY KIND, either  express or implied.  See  the License
 * for the specific language governing permissions  and limitations under
 * the License.
 * 
 **************************************************************************/
 
#include <fstream>    // for filebuf, ifstream, istream
#include <iostream>   // for cout, endl
#include <cstdio>     // for tmpnam(), remove()

#include <examples.h>

int main ()
{
#ifndef _RWSTD_NO_EXT_FILEBUF

    // use an extension of this implementation: NULL file name argument
    // creates a temporary file; closing the file stream object or its
    // associated filebuf removes the temporary file
    const char* const fname = 0;
    
#else   // if defined (_RWSTD_NO_EXT_FILEBUF)

    char fnamebuf [L_tmpnam];

    // create a temporary filename
    const char* const fname = std::tmpnam (fnamebuf);

    if (!fname)
        return 1;

#endif   // _RWSTD_NO_EXT_FILEBUF

    // create a filebuf object for reading and writing of a temporary file
    std::filebuf outbuf;

    outbuf.open (fname, std::ios::in | std::ios::out | std::ios::trunc);

    // set the internal character buffer size
    // buffer will be allocated internally and deallocated in object dtor
    outbuf.pubsetbuf (0, 256);
 
    // associate the filebuf object with an iostream object
    std::iostream out (&outbuf);

    // open this source code file and output it to the temporary file
    out << std::ifstream (__FILE__).rdbuf ();
  
    // seek to the beginning of the stream
    out.seekp (0);

    // output the contents of the `out' object to standard output
    std::cout << out.rdbuf ();  

    // close the filebuf object before removing the underlying file
    outbuf.close ();
  
    if (fname) {
        // remove the temporary file if it has a name
        // otherwise, if fname is NULL, the temporary file will
        // have already been automatically removed by the call
        // to close() above
        std::remove (fname);
    }

    return 0;
}