(open filename io_mode)
The open function opens a file, specified by filename, to read or write.
The argument io_mode specifies :
| IO Mode | Meaning |
|---|---|
| "r" | Opens for reading. If the file does not exist or cannot be found, it returns nil. |
| "w" | Opens an empty file for writing. If the given file exists, its contents are destroyed. |
| "a" | Opens for writing at the end of the file (appending); creates the file first if it does not exist. |
The function returns a file descriptor to be used by other I/O functions.
Examples
: (setq d (open "test.txt" "w"))
: (setq d (open "test.txt" "r"))
: (setq d (open "test.txt" "a"))