Is sqlite locked during .backup

Question

While a backup of a sqlite db is going on (via the .backup command), is the sqlite db locked to prevent writes?

This answer seems to suggest that the db is not locked.

sqlite3 shell command '.backup' and transaction

However, I could not find a definite source in the documentation.

Answer 1

According to the documentation a shared (read-only) lock is acquired.

http://www.sqlite.org/backup.html