To open a device using DosOpen, the application must supply the reserved name for that device. For example, to open the console (both keyboard and screen), you must specify the name CON.
The following table shows some of the common reserved device names:
Common Device Names
旼컴컴컴컴컴쩡컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴커 쿏evice Name쿏escription � 쳐컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 쿎ON 쿟he system console. This device consists of both � � 퀃he keyboard and the screen. You can open CON for � � 퀁eading (from the keyboard), writing (to the � � 퀂creen), or both. � 쳐컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 쿎OM1 쿞erial port 1. You can open this device for � � 퀁eading, writing, or both. Other serial ports will� � 쿴ave names in ascending sequence-COM2, COM3, and � � 퀂o on. � 쳐컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 쿛RN 쿟he default printer port. This device corresponds � � 퀃o one of the system's parallel ports, usually � � 쿗PT1. You can open it for writing but not for � � 퀁eading. � 쳐컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 쿗PT1 쿛arallel port 1. You can open this device for � � 퀇riting but not for reading. Other parallel ports � � 퀇ill have names in ascending sequence-LPT2, LPT3, � � 쿪nd so on. � 쳐컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 쿙UL 쿟he null device. This device provides a method of � � 쿭iscarding output. If you open this device for � � 퀇riting, any data written to the file is � � 쿭iscarded. If you open the device for reading, any� � 쿪ttempt to read from the file returns an � � 쿮nd-of-file mark. � 쳐컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 쿞CREEN$ 쿟he screen. This device can be written to but not � � 퀁ead from. Writing to the screen is similar to � � 퀇riting to the system console. Bytes are displayed� � 쿪s characters (unless the ANSI screen driver is � � 쿹oaded and the character represents an ANSI escape� � 퀂equence). � 쳐컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 쿖BD$ 쿟he keyboard. This device can be read from but not� � 퀇ritten to. Reading from the keyboard is similar � � 퀃o reading from the system console. � 읕컴컴컴컴컴좔컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴켸
After an application uses a device, it should close it by using DosClose.