Read File

\i S R byte::handle word::count

Parameter	Type	Range	Description
handle	byte	0 ... 3	unique identifier for opened file
count	word	0 ... 65535	bytes to read

Reads count bytes from a previously opened file with ID handle from the current position of the file pointer (see Set Position in File).

Note

The requested number of bytes are returned as a byte stream.
After the operation, the file pointer is set to the position after the last byte read.
If the end of file is reached before all data is sent, the remaining bits are sent as zeroes followed by an [ACK].
When an end of file condition exists at the beginning of the read command, no data is sent at all, instead a [NACK] is sent and the error code is set to END_OF_FILE (see Error Codes).
When wanting to read all data from a file, read commands have to be issued until a [NACK] is returned. The error code END_OF_FILE should be checked then. Another approach is using the Get File Status command to request the filesize and then read the exact number of bytes.

Response:

[ACK] data [ACK]

Example

\iSO\2R/DIR1/FILE.EXT\0
\iSS\2\L25
\iSR\2\D4

Opens the file "FILE.EXT" in folder "DIR1" with handle 2 in read-only mode, sets the file pointer to position 25 and reads 4 bytes.

Response Example

[ACK][00][01][02][03][ACK]

The four bytes requested contain ascending values, the file pointer is moved after the last byte read (in this case position 29).

Not supported by: DPC3050, DPC3020, DPC2060, DPC10xx