Updated: 2021/Apr/14

SQLITE3_MUTEX_HELD(3)      Library Functions Manual      SQLITE3_MUTEX_HELD(3)

     sqlite3_mutex_held, sqlite3_mutex_notheld - Mutex Verification Routines



     The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines are
     intended for use inside assert() statements.  The SQLite core never uses
     these routines except inside an assert() and applications are advised to
     follow the lead of the core.  The SQLite core only provides
     implementations for these routines when it is compiled with the
     SQLITE_DEBUG flag.  External mutex implementations are only required to
     provide these routines if SQLITE_DEBUG is defined and if NDEBUG is not

     These routines should return true if the mutex in their argument is held
     or not held, respectively, by the calling thread.

     The implementation is not required to provide versions of these routines
     that actually work.  If the implementation does not provide working
     versions of these routines, it should at least provide stubs that always
     return true so that one does not get spurious assertion failures.

     If the argument to sqlite3_mutex_held() is a NULL pointer then the
     routine should return 1.  This seems counter-intuitive since clearly the
     mutex cannot be held if it does not exist.  But the reason the mutex does
     not exist is because the build is not using mutexes.  And we do not want
     the assert() containing the call to sqlite3_mutex_held() to fail, so a
     non-zero return is the appropriate thing to do.  The
     sqlite3_mutex_notheld() interface should also return 1 when given a NULL

NetBSD 9.99                    December 19, 2018                   NetBSD 9.99