Opening and Closing Files
निर्धारित फ़ाइल को बन्द करता है जो ओपन कथन से खोला गया होता है.
Returns the next available file number for opening a file. Use this function to open a file using a file number that is not already in use by a currently open file.
Closes all open files and writes the contents of all file buffers to the harddisk.