R-20790-14025:[The sqlite3_threadsafe() function returns zero if and only if SQLite was compiled with mutexing code omitted due to the SQLITE_THREADSAFE compile-time option being set to 0. ]
SQLite can be compiled with or without mutexes. When the SQLITE_THREADSAFE C preprocessor macro is 1 or 2, mutexes are enabled and SQLite is threadsafe. When the SQLITE_THREADSAFE macro is 0, the mutexes are omitted. Without the mutexes, it is not safe to use SQLite concurrently from more than one thread.
Enabling mutexes incurs a measurable performance penalty. So if speed is of utmost importance, it makes sense to disable the mutexes. But for maximum safety, mutexes should be enabled. R-07272-22309:[The default behavior is for mutexes to be enabled. ]
This interface can be used by an application to make sure that the version of SQLite that it is linking against was compiled with the desired setting of the SQLITE_THREADSAFE macro.
This interface only reports on the compile-time mutex setting of the SQLITE_THREADSAFE flag. If SQLite is compiled with SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but can be fully or partially disabled using a call to sqlite3_config() with the verbs SQLITE_CONFIG_SINGLETHREAD, SQLITE_CONFIG_MULTITHREAD, or SQLITE_CONFIG_SERIALIZED. R-51445-09984:[The return value of the sqlite3_threadsafe() function shows only the compile-time setting of thread safety, not any run-time changes to that setting made by sqlite3_config(). In other words, the return value from sqlite3_threadsafe() is unchanged by calls to sqlite3_config(). ]
See the threading mode documentation for additional information.
See also lists of Objects, Constants, and Functions.