Programming

ofstream ofs;
int fd = open(fileName, openState, openMode));
func(fd);
......
......
const Boolean func(const int fileDescriptor)
{
    ofs.attach(fileDescriptor);
    if (! ofs)
    {
        closeIt();
        ofs.attach(fileDescriptor);
        if (! ofs)
            return(FAIL);
    }
    return(SUCCESS);
}

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <iostream>
#include <ext/stdio_filebuf.h>  // __gnu_cxx::stdio_filebuf

using namespace std;

int main(void)
{
    std::string str;
    int fd=open("whatever", O_RDONLY); // Get an FD
    FILE *fp=fdopen(fd, "r"); // convert it into a FILE *
    // create a file buffer(NOT an iostream yet) from FILE *
    __gnu_cxx::stdio_filebuf<char> fb (fp, ios_base::in);
    istream fs (&fb);    // create a stream from file buffer

    fs >> str;
    cout << str << endl;
    return(0);
}

#include <fstream.h>
#include <iostream.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <ext/stdio_filebuf.h>  // __gnu_cxx::stdio_filebuf

int main()
{
int fd;
FILE *fp;
if (-1 == (fd=open("/tmp/test.txt", (O_WRONLY|O_CREAT|O_APPEND), 0666)))
{
    cout<<"Unable to open file"<<endl;
    exit(1);
}
cout << "File Descriptor # is: " << fd << endl;
if (NULL == (fp = fdopen(fd, "a")))
{
    cout<<"fdopen failed"<<endl;
    close(fd);
    exit(1);
}

// create a file buffer(NOT an iostream yet) from FILE *
__gnu_cxx::stdio_filebuf<char, std::char_traits<char> > fb (fp, std::ios_base::out);

ostream os(&fb);
os << "Hello World!" << endl;
close(fd); //ostream doesn't have the close() function
return 0;
}

#include <fstream.h>
#include <iostream.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <ext/stdio_filebuf.h>  // __gnu_cxx::stdio_filebuf

int main()
{
int fd;
FILE *fp;
std::ofstream ofs;

if (-1 == (fd=open("/tmp/test.txt", (O_WRONLY|O_CREAT|O_APPEND), 0666)))
{
    cout<<"Unable to open file"<<endl;
    exit(1);
}
cout << "File Descriptor # is: " << fd << endl;
if (NULL == (fp = fdopen(fd, "a")))
{
    cout<<"fdopen failed"<<endl;
    close(fd);
    exit(1);
}

// create a file buffer(NOT an iostream yet) from FILE *
__gnu_cxx::stdio_filebuf<char> fb(fp, std::ios::out);

ofs.std::ios::rdbuf(&fb);
ofs << "Hello World!" << endl;
ofs.close();
return 0;
}