gcc/m2/gm2-libs-iso/StdChans.def

   1 (* Library module defined by the International Standard
   2    Information technology - programming languages
   3    BS ISO/IEC 10514-1:1996E Part 1: Modula-2, Base Language.
   4
   5    Copyright ISO/IEC (International Organization for Standardization
   6    and International Electrotechnical Commission) 1996-2021.
   7
   8    It may be freely copied for the purpose of implementation (see page
   9    707 of the Information technology - Programming languages Part 1:
  10    Modula-2, Base Language.  BS ISO/IEC 10514-1:1996).  *)
  11
  12 DEFINITION MODULE StdChans;
  13
  14   (* Access to standard and default channels *)
  15
  16 IMPORT IOChan;
  17
  18 TYPE
  19   ChanId = IOChan.ChanId;
  20     (* Values of this type are used to identify channels *)
  21
  22   (* The following functions return the standard channel values.
  23      These channels cannot be closed.
  24   *)
  25
  26 PROCEDURE StdInChan (): ChanId;
  27   (* Returns the identity of the implementation-defined standard source for
  28 program
  29      input.
  30   *)
  31
  32 PROCEDURE StdOutChan (): ChanId;
  33   (* Returns the identity of the implementation-defined standard source for program
  34      output.
  35   *)
  36
  37 PROCEDURE StdErrChan (): ChanId;
  38   (* Returns the identity of the implementation-defined standard destination for program
  39      error messages.
  40   *)
  41
  42 PROCEDURE NullChan (): ChanId;
  43   (* Returns the identity of a channel open to the null device. *)
  44
  45   (* The following functions return the default channel values *)
  46
  47 PROCEDURE InChan (): ChanId;
  48   (* Returns the identity of the current default input channel. *)
  49
  50 PROCEDURE OutChan (): ChanId;
  51   (* Returns the identity of the current default output channel. *)
  52
  53 PROCEDURE ErrChan (): ChanId;
  54   (* Returns the identity of the current default error message channel. *)
  55
  56   (* The following procedures allow for redirection of the default channels *)
  57
  58 PROCEDURE SetInChan (cid: ChanId);
  59   (* Sets the current default input channel to that identified by cid. *)
  60
  61 PROCEDURE SetOutChan (cid: ChanId);
  62   (* Sets the current default output channel to that identified by cid. *)
  63
  64 PROCEDURE SetErrChan (cid: ChanId);
  65   (* Sets the current default error channel to that identified by cid. *)
  66
  67 END StdChans.