34 lines
1.2 KiB
Groff
34 lines
1.2 KiB
Groff
.Dd December 19, 2018
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.Dt SQLITE3_SNAPSHOT_CMP 3
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.Os
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.Sh NAME
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.Nm sqlite3_snapshot_cmp
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.Nd Compare the ages of two snapshot handles.
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.Sh SYNOPSIS
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.Ft int
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.Fo sqlite3_snapshot_cmp
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.Fa "sqlite3_snapshot *p1"
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.Fa "sqlite3_snapshot *p2 "
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.Fc
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.Sh DESCRIPTION
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The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
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of two valid snapshot handles.
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.Pp
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If the two snapshot handles are not associated with the same database
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file, the result of the comparison is undefined.
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.Pp
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Additionally, the result of the comparison is only valid if both of
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the snapshot handles were obtained by calling sqlite3_snapshot_get()
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since the last time the wal file was deleted.
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The wal file is deleted when the database is changed back to rollback
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mode or when the number of database clients drops to zero.
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If either snapshot handle was obtained before the wal file was last
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deleted, the value returned by this function is undefined.
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.Pp
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Otherwise, this API returns a negative value if P1 refers to an older
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snapshot than P2, zero if the two handles refer to the same database
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snapshot, and a positive value if P1 is a newer snapshot than P2.
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.Pp
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This interface is only available if SQLite is compiled with the SQLITE_ENABLE_SNAPSHOT
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option.
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