gm2-libs-iso/StdChans (The GNU Modula-2 Compiler)

#### 4.4.65 gm2-libs-iso/StdChans ¶

    DEFINITION MODULE StdChans;

      (* Access to standard and default channels *)

    IMPORT IOChan;

    TYPE
      ChanId = IOChan.ChanId;
        (* Values of this type are used to identify channels *)

      (* The following functions return the standard channel values.
         These channels cannot be closed.
      *)

    PROCEDURE StdInChan (): ChanId;
      (* Returns the identity of the implementation-defined standard source for
    program
         input.
      *)

    PROCEDURE StdOutChan (): ChanId;
      (* Returns the identity of the implementation-defined standard source for program
         output.
      *)

    PROCEDURE StdErrChan (): ChanId;
      (* Returns the identity of the implementation-defined standard destination for program
         error messages.
      *)

    PROCEDURE NullChan (): ChanId;
      (* Returns the identity of a channel open to the null device. *)

      (* The following functions return the default channel values *)

    PROCEDURE InChan (): ChanId;
      (* Returns the identity of the current default input channel. *)

    PROCEDURE OutChan (): ChanId;
      (* Returns the identity of the current default output channel. *)

    PROCEDURE ErrChan (): ChanId;
      (* Returns the identity of the current default error message channel. *)

      (* The following procedures allow for redirection of the default channels *)

    PROCEDURE SetInChan (cid: ChanId);
      (* Sets the current default input channel to that identified by cid. *)

    PROCEDURE SetOutChan (cid: ChanId);
      (* Sets the current default output channel to that identified by cid. *)

    PROCEDURE SetErrChan (cid: ChanId);
      (* Sets the current default error channel to that identified by cid. *)

    END StdChans.