@FILEOPEN

@FILEOPEN[filename, read | write | append, [b | t]]:  Opens the file in 
the specified mode and returns the file handle as an integer.  Returns 
"-1" if the file cannot be opened. 

The optional third parameter controls whether the file is opened in binary 
mode ("b") or text mode ("t").  Text mode (the default) should be used to 
read text using @FILEREAD without a "length" parameter, and to write text 
using @FILEWRITE.  Binary mode should be used to read binary data with 
@FILEREAD with a "length" parameter, and to write binary data with 
@FILEWRITEB. 

Be sure to read the cautionary note about file functions under Variable 
Functions. 

@FILEOPEN can also open named pipes.  The pipe name must begin with 
\pipe\.  @FILEOPEN first tries to open an existing pipe; if that fails it 
tries to create a new pipe.  Pipes are opened in blocking mode, duplex 
access, byte-read mode, and inheritable.  For more information on named 
pipes see your OS/2 documentation.