Device Characteristics

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## SQLite C Interface

## Device Characteristics

>     #define SQLITE_IOCAP_ATOMIC                 0x00000001
>     #define SQLITE_IOCAP_ATOMIC512              0x00000002
>     #define SQLITE_IOCAP_ATOMIC1K               0x00000004
>     #define SQLITE_IOCAP_ATOMIC2K               0x00000008
>     #define SQLITE_IOCAP_ATOMIC4K               0x00000010
>     #define SQLITE_IOCAP_ATOMIC8K               0x00000020
>     #define SQLITE_IOCAP_ATOMIC16K              0x00000040
>     #define SQLITE_IOCAP_ATOMIC32K              0x00000080
>     #define SQLITE_IOCAP_ATOMIC64K              0x00000100
>     #define SQLITE_IOCAP_SAFE_APPEND            0x00000200
>     #define SQLITE_IOCAP_SEQUENTIAL             0x00000400
>     #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
>     #define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000

The xDeviceCharacteristics method of the sqlite3_io_methods object returns an integer which is a vector of these bit values expressing I/O characteristics of the mass storage device that holds the file that the sqlite3_io_methods refers to.

The SQLITE_IOCAP_ATOMIC property means that all writes of any size are atomic. The SQLITE_IOCAP_ATOMICnnn values mean that writes of blocks that are nnn bytes in size and are aligned to an address which is an integer multiple of nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means that when data is appended to a file, the data is appended first then the size of the file is extended, never the other way around. The SQLITE_IOCAP_SEQUENTIAL property means that information is written to disk in the same order as calls to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that after reboot following a crash or power loss, the only bytes in a file that were written at the application level might have changed and that adjacent bytes, even bytes within the same sector are guaranteed to be unchanged.

See also lists of Objects, Constants, and Functions.