OPEN

Description

This command can be used to open an existing file for reading.

Parameters

The command needs two arguments. First a handle number in the range from 0 to 100 and next the name (or full path) of a file. If open succeeds, the given handle number must be used in subsequent calls to other operations on that file.

Return Value

ERR_OK (0) if the file was opened successfully.
ERR_ID_USED (27) if the handle is already in use (e.g. by another file).
ERR_FILE_OPEN (32) if the file is aready in use (opened for reading or writing)
ERR_FIL_EXHAUSTED (26) if the system couldn't allocate a file descriptor for that file.
ERR_FR_... (13...25) file system errors if the file system encountered an error.

Example

OPEN 1 hello.txt 

The file hello.txt is opened for reading as handle #1

Remarks

Before an existing file can be read ist must be opened using OPEN. When done, use the CLOSE command to close the file and free the file handle.

 

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OPEN?

Description

OPEN? can be used to print all file handles that are currently open. A file is in open state, when its handle is in use (activated by OPEN, NEW oer APPD). OPEN? does not require any arguments. The output is a list of all open files separated by comma.

Example

OPEN?

If e.g handles 1,4 and 5 are open, OPEN? prints: 1,4,5