## function OpenFile(fileName$, mode)

Returns an ID for an open file to read or write.

Returns -1 if the file could not be opened.

Possible Text Modes

- TEXT_INPUT - Open a file for reading text. The file must already exist.
- TEXT_OUTPUT - Open a new file for writing text. If the file already exist it will be overwritten.
- TEXT_APPEND - Opens a file for appending text to the end of the file. A file will be created if it doesn't already exist.
- TEXT_INPUT_PLUS - Opens a file for reading and writing text. The file must already exist.
- TEXT_OUTPUT_PLUS - Opens a file for both reading and writing. If the file already exist it will be overwritten.
- TEXT_APPEND_PLUS - Opens a file for reading and appending text to the end of the file.

Possible Binary Modes

- BINARY_INPUT - Open a file for reading binary data. The file must already exist.
- BINARY_OUTPUT - Open a new file for writing binary data. If the file already exist it will be overwritten.
- BINARY_APPEND - Opens a file for appending binary data to the end of the file. A file will be created if it doesn't already exist.
- BINARY_INPUT_PLUS - Opens a file for reading and writing binary data. The file must already exist.
- BINARY_OUTPUT_PLUS - Opens a file for both reading and writing. If the file already exist it will be overwritten.
- BINARY_APPEND_PLUS - Opens a file for reading and appending binary data to the end of the file.