Docs » Autodocs » parallel.device » CMD_READ
Read -- read input from parallel port
This command causes a stream of characters to be read from the
parallel I/O register. The number of characters is specified in
io_Length. The EOF and EOL modes are supported, but be warned that
using these modes can result in a buffer overflow if the proper
EOL or EOF character is not received in time. These modes should
be used only when the sender and receiver have been designed to
cooperate. A safety guard can be implemented to EOF by setting
io_Length to a maximum allowed value. That cannot be done with EOL
since the EOL mode is identified by io_Length=-1.
The parallel.device has no internal buffer; if no read request has
been made, pending input (i.e. handshake request) is not
io_Message mn_ReplyPort initialized
io_Device set by OpenDevice
io_Unit set by OpenDevice
io_Command CMD_READ (02)
io_Flags If IOF_QUICK is set, driver will attempt Quick IO
io_Length number of characters to receive.
io_Data pointer where to put the data.
io_Error -- if the Read succeded, then io_Error will be null.parallel.device/PDCMD_SETPARAMS()
If the Read failed, then io_Error will contain an error code.