title: Using the open() system call
body: <p>I'm writing a program that writes output to a file. If this file doesn't exist, I want to create it.</p>
  
  <p>Currently, I'm using the following flags when calling open:
  O_WRONLY | O_CREATE</p>
  
  <p>However, when this creates the file, it doesn't give me any permissions to write to it...</p>
  
  <p>How can I use open so that it creates a file if it doesn't exist, but will create it with necessary permissions when needed?</p>
  
  <p>Thanks!</p>