SQLITE_IOCAP_ATOMIC(3) | Library Functions Manual | SQLITE_IOCAP_ATOMIC(3)

# NAME

`SQLITE_IOCAP_ATOMIC`, `SQLITE_IOCAP_ATOMIC512`, `SQLITE_IOCAP_ATOMIC1K`, `SQLITE_IOCAP_ATOMIC2K`, `SQLITE_IOCAP_ATOMIC4K`, `SQLITE_IOCAP_ATOMIC8K`, `SQLITE_IOCAP_ATOMIC16K`, `SQLITE_IOCAP_ATOMIC32K`, `SQLITE_IOCAP_ATOMIC64K`, `SQLITE_IOCAP_SAFE_APPEND`, `SQLITE_IOCAP_SEQUENTIAL`, `SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN`, `SQLITE_IOCAP_POWERSAFE_OVERWRITE`, `SQLITE_IOCAP_IMMUTABLE`, `SQLITE_IOCAP_BATCH_ATOMIC` —
Device Characteristics

# SYNOPSIS

`#define SQLITE_IOCAP_ATOMIC`
`#define SQLITE_IOCAP_ATOMIC512`
`#define SQLITE_IOCAP_ATOMIC1K`
`#define SQLITE_IOCAP_ATOMIC2K`
`#define SQLITE_IOCAP_ATOMIC4K`
`#define SQLITE_IOCAP_ATOMIC8K`
`#define SQLITE_IOCAP_ATOMIC16K`
`#define SQLITE_IOCAP_ATOMIC32K`
`#define SQLITE_IOCAP_ATOMIC64K`
`#define SQLITE_IOCAP_SAFE_APPEND`
`#define SQLITE_IOCAP_SEQUENTIAL`
`#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN`
`#define SQLITE_IOCAP_POWERSAFE_OVERWRITE`
`#define SQLITE_IOCAP_IMMUTABLE`
`#define SQLITE_IOCAP_BATCH_ATOMIC`

# DESCRIPTION

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. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN flag indicates that a file cannot be deleted when open. The SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on read-only media and cannot be changed even by processes with elevated privileges.

The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying filesystem supports doing multiple write operations atomically when those write operations are bracketed by SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and SQLITE_FCNTL_COMMIT_ATOMIC_WRITE.

# SEE ALSO

sqlite3_io_methods(3), SQLITE_FCNTL_LOCKSTATE(3)

December 19, 2018 | NetBSD 9.5