f$FileOpen (f$DateiÖffnen)

Open a file for reading or writing. A file number is returned which identifies the opened file for further read/write operations. To ensure that an input file also exists or that an already existing file is not overwritten with an output file, you can check the existence of a file beforehand with the f$FileExists function.

Please note that, when entering a path in the file name, the character "\" must be entered twice ("\\").

Syntax:	FileNo = f$FileOpen( Filename, Mode )
	Argument	Type	Meaning
	Filename	String	File name including path
	Mode	String	Mode of access to the file: 'r': read an existing file 'w': write into new file 'a': write (attach) into existing file 'r+': read and write into existing file 'w+': read and write into new file 'a+': attach into existing or new file 'b' : open as binary file. This option can be combined with other options, e.g. 'wb' write binary to a new file.
Result:	Integer	File number or 0 if the file cannot be opened.
Example:	No = f$FileOpen( 'c:\\customers\\customer.txt', 'r' ) → The file is opened for reading