EBADF using write() in C

[blipt]

I just started messing around in Linux programming, and I wanted to create a simple test program to open a file, read to it, and write to it. I can open and read it, but write always gives errno = EBADF. I've messed with file creation permissions and I can figure out why write() thinks it's a bad file descriptor but not read(). Any help would be appreciated.

Here is my code:


#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <unistd.h>

#include <iostream>

#include <string.h>

#include <stdio.h>

using namespace std;

int main()
{
cout << "Hello World!\n";

int fd;
fd = open("/home/mike/OPEN.txt",O_APPEND | O_CREAT | O_NONBLOCK, (mode_t)0x666);

cout << fd << endl;

char *buf;
ssize_t readret;
readret = read(fd, buf, (size_t)10);

cout << buf[0];
perror("read");

ssize_t ret;
char *words = "What up";
ret = write(fd, words, (size_t)strlen(words));

cout << ret;
perror("write");

close(fd);

[blipt]

Haha I found it!

open() must use one of these flags among others:

O_RDONLY, O_WRONLY, O_RDWR

using O_RDWR makes it work.