[Dev-C++] first time error return on checking file stream validity

[Alan T. <ala...@3n...>]

The code below gives some interesting results.  First return from the
function start_HTML_file is 0 (no error), while the second time it =
returns 1
(could not open file).  What does this mean?
                                                        Thanks, Alan

#include <iostream.h>
#include <stdlib.h>
#include <fstream.h>
#include <string.h>

// define HTML author
const char *Author =3D "Alan Thomas";

//
// function prototype
//
int start_HTML_file (ofstream&output_file, char *keywords =3D NULL,
    char *title =3D NULL);


int main()
{
 ofstream invalid; // used to test for error opening file

  // Test invalid file checking
 cout << "Error return was " << start_HTML_file (invalid, NULL,
                "This is the title") << endl;
 cout << "Error return was " << start_HTML_file (invalid, NULL,
                "This is the title") << endl;

 system("PAUSE");

 return 0;
}

int start_HTML_file (ofstream&output_file, char *keywords =3D NULL, char
*title =3D NULL)
{
 if (!output_file)
    {
     cout << "Error opening file." << endl;
     return 1; // error indication
    }
 // Write header information
 output_file << "<!doctype html public \"-//w3c//dtd html 4.0
transitional//en\">";
 output_file << endl;
 output_file << "<html>" << endl;
 output_file << "<head>" << endl;
 output_file << "<meta http-equiv=3D\"Content-Type\" =
content-\"text/html;
charset=3Diso-8859-1\"";
 output_file << endl;
 output_file << "<meta name=3D\"Author\" content=3D\"" << Author << =
"\">" <<
endl;
 if (keywords !=3D NULL)
    {
     output_file << "<meta name=3D\"KeyWords\" content=3D\"";
     output_file << keywords << ">\"" << endl;
    }
 // Write out title
 if (title !=3D NULL)
    {
     output_file << "<title>";
     output_file << title;
     output_file << "</title>" << endl;
    }
 // End header
 output_file << "</head>" << endl;

 return 0;
}