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Command: sqlite3_progress_handler | Section: 3 | Source: NetBSD | File: sqlite3_progress_handler.3
SQLITE3_PROGRESS_HANDLER(3) FreeBSD Library Functions Manual
NAME
sqlite3_progress_handler - Query Progress Callbacks
SYNOPSIS
void
sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
DESCRIPTION
The sqlite3_progress_handler(D,N,X,P) interface causes the callback
function X to be invoked periodically during long running calls to
sqlite3_exec(), sqlite3_step() and sqlite3_get_table() for database
connection D. An example use for this interface is to keep a GUI updated
during a large query.
The parameter P is passed through as the only parameter to the callback
function X. The parameter N is the approximate number of virtual machine
instructions that are evaluated between successive invocations of the
callback X. If N is less than one then the progress handler is disabled.
Only a single progress handler may be defined at one time per database
connection; setting a new progress handler cancels the old one. Setting
parameter X to NULL disables the progress handler. The progress handler
is also disabled by setting N to a value less than 1.
If the progress callback returns non-zero, the operation is interrupted.
This feature can be used to implement a "Cancel" button on a GUI progress
dialog box.
The progress handler callback must not do anything that will modify the
database connection that invoked the progress handler. Note that
sqlite3_prepare_v2() and sqlite3_step() both modify their database
connections for the meaning of "modify" in this paragraph.
SEE ALSO
sqlite3(3), sqlite3_exec(3), sqlite3_get_table(3), sqlite3_prepare(3),
sqlite3_step(3)
FreeBSD 14.1-RELEASE-p8 December 19, 2018 FreeBSD 14.1-RELEASE-p8