What file mode, access and share is used in php's file_get_contents

In C# on Windows File.Open()-method has the following function definition:

• File.Open(String fileName, FileMode mode, FileAccess access, FileShare share).

Source: http://ift.tt/1C6pWJx

Where the parameters can have the following values:

• FileMode: Append, Create, CreateNew, Open, OpenOrCreate, Truncate


• FileAccess: Read, ReadWrite, Write


• FileShare: Delete, Inheritable, None, Read, ReadWrite, Write
  
  
  

Main question

Which FileMode, FileAccess and FileShare is used for file_get_contents in php on Windows?

Side question 1

How can FileAccess and FileShare be influenced for file_get_contents or fopen in php on Windows?

Side question 2

Can two or more concurrent processes on windows use file_get_contents for the same file?

Thank you very much in advance.