Function SelectText ( var T : Text; TimeOut :PTime) : Longint;
SelectText executes the Select call on a file of type Text. You can specify a timeout in TimeOut. The SelectText call determines itself whether it should check for read or write, depending on how the file was opened : With Reset it is checked for reading, with Rewrite and Append it is checked for writing.
See Select. SYS_EBADF can also mean that the file wasn't opened.