The only allowed file
modes for text files are the modes In_File, Out_File, and Append_File.
The subprograms given in subclause
A.8.2
for the control of external files, and the function End_Of_File given
in subclause
A.8.3 for sequential input-output,
are also available for text files. There is also a version of End_Of_File
that refers to the current default input file. For text files, the procedures
have the following additional effects:
The exception Mode_Error is propagated by the procedure
Reset upon an attempt to change the mode of a file that is the current
default input file, the current default output file, or the current default
error file.
22 An implementation
can define the Form parameter of Create and Open to control effects including
the following: