What happens if you attempt to read from a file that has been opened in 'w' mode?

When a file is opened in 'w' mode, it is specifically designated for writing. In this mode, the file is cleared of any existing content (if it already exists) and is made ready to accept new data. Attempting to read from a file opened in 'w' mode will not succeed because the file is not opened with the appropriate permissions for reading; it is strictly for writing only.

This restriction is built into file handling protocols to ensure that data integrity is maintained while writing, and it prevents unintentional reading while in a write-only state. Thus, if you try to perform a read operation on a file that is in 'w' mode, the operation will fail, likely resulting in an error indicating that the file isn't open for reading.