1.Dd January 24, 2024 2.Dt SQLITE_SHM_UNLOCK 3 3.Os 4.Sh NAME 5.Nm SQLITE_SHM_UNLOCK , 6.Nm SQLITE_SHM_LOCK , 7.Nm SQLITE_SHM_SHARED , 8.Nm SQLITE_SHM_EXCLUSIVE 9.Nd flags for the xShmLock VFS method 10.Sh SYNOPSIS 11.In sqlite3.h 12.Fd #define SQLITE_SHM_UNLOCK 13.Fd #define SQLITE_SHM_LOCK 14.Fd #define SQLITE_SHM_SHARED 15.Fd #define SQLITE_SHM_EXCLUSIVE 16.Sh DESCRIPTION 17These integer constants define the various locking operations allowed 18by the xShmLock method of sqlite3_io_methods. 19The following are the only legal combinations of flags to the xShmLock 20method: 21.Bl -bullet 22.It 23SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 24.It 25SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 26.It 27SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 28.It 29SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 30.El 31.Pp 32When unlocking, the same SHARED or EXCLUSIVE flag must be supplied 33as was given on the corresponding lock. 34.Pp 35The xShmLock method can transition between unlocked and SHARED or between 36unlocked and EXCLUSIVE. 37It cannot transition between SHARED and EXCLUSIVE. 38.Sh IMPLEMENTATION NOTES 39These declarations were extracted from the 40interface documentation at line 1529. 41.Bd -literal 42#define SQLITE_SHM_UNLOCK 1 43#define SQLITE_SHM_LOCK 2 44#define SQLITE_SHM_SHARED 4 45#define SQLITE_SHM_EXCLUSIVE 8 46.Ed 47.Sh SEE ALSO 48.Xr sqlite3_io_methods 3 49