Function            CEDadd - add a CED installable command

  Syntax              boolean CEDadd(char *command, unsigned char mode,
                                     unsigned segment, unsigned offset);

  Prototype in        doshk.h

  Remarks             adds a CED installable command. The mode parameter
                      is a bit mask with the following settings:

                           bit 0 = 1      callable from DOS prompt
                           bit 1 = 1      callable from application

                      command should be terminated by a CR.

                      The segment:offset parameters point to a FAR
                      routine entry point.

  Return value        returns TRUE if successful, FALSE otherwise. If
                      unsuccessful, _doserrno will contain the error
                      code:

                           0x01      invalid function
                           0x08      insufficient memory
                           0x0E      bad data

                      If CED is not installed, _doserrno & 0xFF00 will
                      return 0xFF00.

  See also            CEDremove(), isCEDavail()