title: Can you read a file concurrently with writing to a file using file_put_contents?
body: <p>When a user lands on the page, I want to write some information about their browser/ip/location to a file.<br>
  At the top of the file I have some PHP code that checks my cookie and if I am admin will echo the contents of the file to the page so I can see the list of visitor data (using file_get_contents). I am going to make a function that will display the data in a table at some point.</p>
  
  <p>I am tempted to use file_put_contents with the FILE_APPEND flag is set because it looks easy to use. Would there be any file permission conflicts with reading and writing to the file, and if so, how does fopen/fwrite avoid this conflict?</p>